#!/bin/bash
#
#
# mklove base configure module, implements the mklove configure framework
#

MKL_MODULES="base"
MKL_CACHEVARS="CFLAGS LDFLAGS PKG_CONFIG_PATH"
MKL_MKVARS=""
MKL_DEFINES=""
MKL_CHECKS=""
MKL_LOAD_STACK=""

MKL_IDNEXT=1

# Default mklove directory to PWD/mklove
[[ -z "$MKLOVE_DIR" ]] && MKLOVE_DIR="$PWD/mklove"

MKL_OUTMK="$PWD/_mklout.mk"
MKL_OUTH="$PWD/_mklout.h"
MKL_OUTDBG="$PWD/config.log"

MKL_GENERATORS="base:mkl_generate_late_vars"
MKL_CLEANERS=""

MKL_FAILS=""
MKL_LATE_VARS=""

MKL_OPTS_SET=""

MKL_RED=""
MKL_GREEN=""
MKL_YELLOW=""
MKL_BLUE=""
MKL_CLR_RESET=""


MKL_NO_DOWNLOAD=0
MKL_INSTALL_DEPS=n
MKL_SOURCE_DEPS_ONLY=n

MKL_DESTDIR_ADDED=n

if [[ -z "$MKL_REPO_URL" ]]; then
    MKL_REPO_URL="http://github.com/edenhill/mklove/raw/master"
fi



###########################################################################
#
# Variable types:
#   env      - Standard environment variables.
#   var      - mklove runtime variable, cached or not.
#   mkvar    - Makefile variables, also sets runvar
#   define   - config.h variables/defines
#
###########################################################################

# Low level variable assignment
# Arguments:
#  variable name
#  variable value
function mkl_var0_set {
    export "$1"="$2"
}

# Sets a runtime variable (only used during configure)
# If "cache" is provided these variables are cached to config.cache.
# Arguments:
#  variable name
#  variable value
#  [ "cache" ]
function mkl_var_set {
    mkl_var0_set "$1" "$2"
    if [[ $3 == "cache" ]]; then
        if ! mkl_in_list "$MKL_CACHEVARS" "$1" ; then
            MKL_CACHEVARS="$MKL_CACHEVARS $1"
        fi
    fi
}

# Unsets a mkl variable
# Arguments:
#  variable name
function mkl_var_unset {
    unset $1
}

# Appends to a mkl variable (space delimited)
# Arguments:
#  variable name
#  variable value
function mkl_var_append {
    if [[ -z ${!1} ]]; then
        mkl_var_set "$1" "$2"
    else
        mkl_var0_set "$1" "${!1} $2"
    fi
}


# Prepends to a mkl variable (space delimited)
# Arguments:
#  variable name
#  variable value
function mkl_var_prepend {
    if [[ -z ${!1} ]]; then
        mkl_var_set "$1" "$2"
    else
        mkl_var0_set "$1" "$2 ${!1}"
    fi
}

# Shift the first word off a variable.
# Arguments:
#  variable name
function mkl_var_shift {
    local n="${!1}"
    mkl_var0_set "$1" "${n#* }"
    return 0
}


# Returns the contents of mkl variable
# Arguments:
#  variable name
function mkl_var_get {
    echo "${!1}"
}




# Set environment variable (runtime)
# These variables are not cached nor written to any of the output files,
# its just simply a helper wrapper for standard envs.
# Arguments:
#  varname
#  varvalue
function mkl_env_set {
    mkl_var0_set "$1" "$2"
}

# Append to environment variable
# Arguments:
#  varname
#  varvalue
#  [ separator (" ") ]
function mkl_env_append {
    local sep=" "
    if [[ -z ${!1} ]]; then
        mkl_env_set "$1" "$2"
    else
        [ ! -z ${3} ] && sep="$3"
        mkl_var0_set "$1" "${!1}${sep}$2"
    fi

}

# Prepend to environment variable
# Arguments:
#  varname
#  varvalue
#  [ separator (" ") ]
function mkl_env_prepend {
    local sep=" "
    if [[ -z ${!1} ]]; then
        mkl_env_set "$1" "$2"
    else
        [ ! -z ${3} ] && sep="$3"
        mkl_var0_set "$1" "$2${sep}${!1}"
    fi

}




# Set a make variable (Makefile.config)
# Arguments:
#  config name
#  variable name
#  value
function mkl_mkvar_set {
    if [[ ! -z $2 ]]; then
        mkl_env_set "$2" "$3"
        mkl_in_list "$MKL_MKVARS" "$2"|| mkl_env_append MKL_MKVARS $2
    fi
}


# Prepends to a make variable (Makefile.config)
# Arguments:
#  config name
#  variable name
#  value
#  [ separator (" ") ]
function mkl_mkvar_prepend {
    if [[ ! -z $2 ]]; then
        mkl_env_prepend "$2" "$3" "$4"
        mkl_in_list "$MKL_MKVARS" "$2"|| mkl_env_append MKL_MKVARS $2
    fi
}


# Appends to a make variable (Makefile.config)
# Arguments:
#  config name
#  variable name
#  value
#  [ separator (" ") ]
function mkl_mkvar_append {
    if [[ ! -z $2 ]]; then
        mkl_env_append "$2" "$3" "$4"
        mkl_in_list "$MKL_MKVARS" "$2"|| mkl_env_append MKL_MKVARS $2
    fi
}


# Prepends to a make variable (Makefile.config)
# Arguments:
#  config name
#  variable name
#  value
#  [ separator (" ") ]
function mkl_mkvar_prepend {
    if [[ ! -z $2 ]]; then
        mkl_env_prepend "$2" "$3" "$4"
        mkl_in_list "$MKL_MKVARS" "$2"|| mkl_env_append MKL_MKVARS $2
    fi
}

# Return mkvar variable value
# Arguments:
#  variable name
function mkl_mkvar_get {
    [[ -z ${!1} ]] && return 1
    echo ${!1}
    return 0
}



# Defines a config header define (config.h)
# Arguments:
#  config name
#  define name
#  define value (optional, default: 1)
#   if value starts with code: then no "" are added
function mkl_define_set {

    if [[ -z $2 ]]; then
        return 0
    fi

    local stmt=""
    local defid=
    if [[ $2 = *\(* ]]; then
        # macro
        defid="def_${2%%(*}"
    else
        # define
        defid="def_$2"
    fi

    [[ -z $1 ]] || stmt="// $1\n"

    local val="$3"
    if [[ -z "$val" ]]; then
        val="$(mkl_def $2 1)"
    fi

    # Define as code, string or integer?
    if [[ $val == code:* ]]; then
        # Code block, copy verbatim without quotes, strip code: prefix
        val=${val#code:}
    elif [[ ! ( "$val" =~ ^[0-9]+([lL]?[lL][dDuU]?)?$ || \
        "$val" =~ ^0x[0-9a-fA-F]+([lL]?[lL][dDuU]?)?$ ) ]]; then
        # String: quote
        val="\"$val\""
    fi
    # else: unquoted integer/hex

    stmt="${stmt}#define $2 $val"
    mkl_env_set "$defid" "$stmt"
    mkl_env_append MKL_DEFINES "$defid"
}





# Sets "all" configuration variables, that is:
# for name set: Makefile variable, config.h define
# Will convert value "y"|"n" to 1|0 for config.h
# Arguments:
#  config name
#  variable name
#  value
function mkl_allvar_set {
    mkl_mkvar_set "$1" "$2" "$3"
    local val=$3
    if [[ $3 = "y" ]]; then
        val=1
    elif [[ $3 = "n" ]]; then
        val=0
    fi
    mkl_define_set "$1" "$2" "$val"
}


###########################################################################
#
# Dependency installation, et.al.
#
#
###########################################################################

# Returns the local dependency directory.
function mkl_depdir {
    local dir="$MKLOVE_DIR/deps"
    [[ -d $dir ]] || mkdir -p "$dir"
    if ! grep -q ^deps$ "$MKLOVE_DIR/.gitignore" 2>/dev/null ; then
        echo "deps" >> "$MKLOVE_DIR/.gitignore"
    fi

    echo "$dir"
}

# Returns the package's installation directory / DESTDIR.
function mkl_dep_destdir {
    echo "$(mkl_depdir)/dest"
}

# Returns the package's source directory.
function mkl_dep_srcdir {
    echo "$(mkl_depdir)/src/$1"
}


# Get the static library file name(s) for a package.
function mkl_lib_static_fnames {
    local name=$1
    mkl_meta_get $name "static" ""
}


# Returns true if previous ./configure ran a dep install for this package.
function mkl_dep_install_cached {
    local name=$1

    if [[ -n $(mkl_var_get "MKL_STATUS_${1}_INSTALL") ]] ||
           [[ -n $(mkl_var_get "MKL_STATUS_${1}_INSTALL_SRC") ]]; then
        return 0 # true
    else
        return 1 # false
    fi
}

# Install an external dependency using the platform's native
# package manager.
# Should only be called from mkl_dep_install
#
# Param 1: config name
function mkl_dep_install_pkg {
    local name=$1
    local iname="${name}_INSTALL"
    local retcode=1  # default to fail
    local method="none"
    local pkgs
    local cmd

    mkl_dbg "Attempting native install of dependency $name on $MKL_DISTRO with effective user $EUID"


    # Try the platform specific installer first.
    case ${MKL_DISTRO}-${EUID} in
        debian-0|ubuntu-0)
            method=apt
            pkgs=$(mkl_meta_get $name deb)
            cmd="apt install -y $pkgs"
            ;;

        centos-0|rhel-0|redhat-0|fedora-0)
            method=yum
            pkgs=$(mkl_meta_get $name rpm)
            cmd="yum install -y $pkgs"
            ;;

        alpine-0)
            method=apk
            pkgs=$(mkl_meta_get $name apk)
            cmd="apk add $pkgs"
            ;;

        osx-*)
            method=brew
            pkgs=$(mkl_meta_get $name brew)
            cmd="brew install $pkgs"
            ;;

        *)
            mkl_dbg "$name: No native installer set for $name on $MKL_DISTRO (euid $EUID)"
            return 1
            ;;
    esac

    if [[ -z $pkgs ]]; then
        mkl_dbg "$name: No packages to install ($method)"
        return 1
    fi

    mkl_check_begin --verb "installing dependencies ($cmd)" $iname "" no-cache "$name"
    $cmd >>$MKL_OUTDBG 2>&1
    retcode=$?

    if [[ $retcode -eq 0 ]]; then
        mkl_dbg "Native install of $name (using $method, $cmd) succeeded"
        mkl_check_done "$iname" "" cont "using $method"
        mkl_meta_set $name installed_with "$method"
    elif [[ $method != "none" ]]; then
        mkl_dbg "Native install of $name (using $method, $cmd) failed: retcode $retcode"
        mkl_check_failed "$iname" "" cont "using $method"
    fi

    return $retcode
}


# Returns 0 (yes) if this dependency has a source builder, else 1 (no)
function mkl_dep_has_builder {
    local name=$1
    local func="${name}_install_source"
    mkl_func_exists $func
}


# Returns 0 (yes) if this dependency has a package installer, else 1 (no)
function mkl_dep_has_installer {
    local name=$1
    if mkl_dep_has_builder "$name" || \
            [[ -n $(mkl_meta_get $name deb) ]] || \
            [[ -n $(mkl_meta_get $name rpm) ]] || \
            [[ -n $(mkl_meta_get $name brew) ]] || \
            [[ -n $(mkl_meta_get $name apk) ]]; then
        return 0
    else
        return 1
    fi
}


# Install an external dependency from source.
#
# The resulting libraries must be installed in $ddir/usr/lib (or lib64),
# and include files in $ddir/usr/include.
#
# Any dependency installed from source will be linked statically
# regardless of --enable-static, if the build produced static libraries.

#
# Param 1: config name
function mkl_dep_install_source {
    local name=$1
    local iname="${name}_INSTALL_SRC"
    local retcode=

    local func="${name}_install_source"

    if ! mkl_dep_has_builder $name ; then
        mkl_dbg "No source builder for $name ($func) available"
        return 1
    fi

    mkl_check_begin --verb "building dependency" $iname "" no-cache "$name"

    # Create install directory / DESTDIR
    local ddir=$(mkl_dep_destdir $name)
    [[ -d $ddir ]] || mkdir -p "$ddir"

    # Create and go to source directory
    local sdir=$(mkl_dep_srcdir $name)
    [[ -d $sdir ]] || mkdir -p "$sdir"
    mkl_pushd "$sdir"

    local ilog="${sdir}/_mkl_install.log"

    # Build and install
    mkl_dbg "Building $name from source in $sdir (func $func)"

    $func $name "$ddir" >$ilog 2>&1
    retcode=$?

    mkl_popd # $sdir

    if [[ $retcode -eq 0 ]]; then
        mkl_dbg "Source install of $name succeeded"
        mkl_check_done "$iname" "" cont "ok" "from source"
        mkl_meta_set $name installed_with "source"
    else
        mkl_dbg "Source install of $name failed"
        mkl_check_failed "$iname" "" disable "source installer failed (see $ilog)"
        mkl_err "$name source build failed, see $ilog for details. First 50 and last 50 lines:"
        head -50 "$ilog"
        echo " .... and last 50 lines ...."
        tail -50 "$ilog"
    fi

    return $retcode
}


# Tries to resolve/find full paths to static libraries for a module,
# using the provided scan dir path.
# Any found libraries are set as STATIC_LIB_.. defines.
#
# Param 1: config name
# Param 2: scandir
#
# Returns 0 if libraries were found, else 1.
function mkl_resolve_static_libs {
    local name="$1"
    local scandir="$2"
    local stlibfnames=$(mkl_lib_static_fnames $name)
    local stlibvar="STATIC_LIB_${name}"

    if [[ -z $stlibfnames || -n "${!stlibvar}" ]]; then
        mkl_dbg "$name: not resolving static libraries (stlibfnames=$stlibfnames, $stlibvar=${!stlibvar})"
        mkl_allvar_set "$name" "WITH_STATIC_LIB_$name" y
        return 1
    fi

    local fname=
    local stlibs=""
    mkl_dbg "$name: resolving static libraries from $stlibfnames in $scandir"
    for fname in $stlibfnames ; do
        local stlib=$(find "${scandir}" -name "$fname" 2>/dev/null | head -1)
        if [[ -n $stlib ]]; then
            stlibs="${stlibs} $stlib"
        fi
    done

    # Trim leading whitespaces
    stlibs=${stlibs# }

    if [[ -n $stlibs ]]; then
        mkl_dbg "$name: $stlibvar: found static libs: $stlibs"
        mkl_var_set $stlibvar "$stlibs" "cache"
        mkl_allvar_set "$name" "WITH_STATIC_LIB_$name" y
        return 0
    else
        mkl_dbg "$name: did not find any static libraries for $stlibfnames in ${scandir}"
        return 1
    fi
}


# Install an external dependecy
#
# Param 1: config name  (e.g zstd)
function mkl_dep_install {
    local name=$1
    local retcode=

    local ddir=$(mkl_dep_destdir $name)

    if [[ $MKL_SOURCE_DEPS_ONLY != y ]] || ! mkl_dep_has_builder $name ; then
        #
        # Try native package manager first, or if no source builder
        # is available for this dependency.
        #
        mkl_dep_install_pkg $name
        retcode=$?

        if [[ $retcode -eq 0 ]]; then
            return $retcode
        fi
    fi

    #
    # Try source installer.
    #
    mkl_dep_install_source $name
    retcode=$?

    if [[ $retcode -ne 0 ]]; then
        if [[ $MKL_SOURCE_DEPS_ONLY == y ]]; then
            # Require dependencies, regardless of original action,
            # if --source-deps-only is specified, to ensure
            # that we do indeed link with the desired library.
            mkl_fail "$name" "" fail "Failed to install dependency $name"
        fi
        return $retcode
    fi

    local ddir=$(mkl_dep_destdir $name)

    # Find the static library(s), if any.
    if ! mkl_resolve_static_libs "$name" "${ddir}/usr"; then
        # No static libraries found, set up dynamic linker path
        mkl_mkvar_prepend LDFLAGS LDFLAGS "-L${ddir}/usr/lib64 -L${ddir}/usr/lib"
    fi

    # Add the deps destdir to various build flags so that tools can pick
    # up the artifacts (.pc files, includes, libs, etc) they need.
    if [[ $MKL_DESTDIR_ADDED == n ]]; then
	# Add environment variables so that later built dependencies
	# can find this one.
	mkl_env_prepend LDFLAGS "-L${ddir}/usr/lib64 -L${ddir}/usr/lib"
	mkl_env_prepend CPPFLAGS "-I${ddir}/usr/include"
        mkl_env_prepend PKG_CONFIG_PATH "${ddir}/usr/lib/pkgconfig" ":"
        # And tell pkg-config to get static linker flags.
	mkl_env_set PKG_CONFIG "${PKG_CONFIG} --static"
	MKL_DESTDIR_ADDED=y
    fi

    # Append the package's install path to compiler and linker flags.
    mkl_dbg "$name: Adding install-deps paths ($ddir) to compiler and linker flags"
    mkl_mkvar_prepend CPPFLAGS CPPFLAGS "-I${ddir}/usr/include"

    return $retcode
}


# Apply patch to a source dependency.
#
# Param 1: config name (e.g. libssl)
# Param 2: patch number (optional, else all)
#
# Returns 0 on success or 1 on error.
function mkl_patch {
    local name=$1
    local patchnr="$2"

    if [[ -z $patchnr ]]; then
        patchnr="????"
    fi

    local patchfile=
    local cnt=0
    for patchfile in $(echo ${MKLOVE_DIR}/modules/patches/${name}.${patchnr}-*.patch | sort); do
        mkl_dbg "$1: applying patch $patchfile"
        patch -p1 < $patchfile
        local retcode=$?
        if [[ $retcode != 0 ]]; then
            mkl_err "mkl_patch: $1: failed to apply patch $patchfile: see source dep build log for details"
            return 1
        fi
        cnt=$(($cnt + 1))
    done

    if [[ $cnt -lt 1 ]]; then
        mkl_err "mkl_patch: $1: no patches matchign $patchnr found"
        return 1
    fi

    return 0
}


###########################################################################
#
#
# Check failure functionality
#
#
###########################################################################


# Summarize all fatal failures and then exits.
function mkl_fail_summary {
    echo "

"

    local pkg_cmd=""
    local install_pkgs=""
    mkl_err "###########################################################"
    mkl_err "###                  Configure failed                   ###"
    mkl_err "###########################################################"
    mkl_err "### Accumulated failures:                               ###"
    mkl_err "###########################################################"
    local n
    for n in $MKL_FAILS ; do
        local conf=$(mkl_var_get MKL_FAIL__${n}__conf)
        mkl_err  " $conf ($(mkl_var_get MKL_FAIL__${n}__define)) $(mkl_meta_get $conf name)"
        if mkl_meta_exists $conf desc; then
            mkl_err0 "      desc: $MKL_YELLOW$(mkl_meta_get $conf desc)$MKL_CLR_RESET"
        fi
        mkl_err0 "    module: $(mkl_var_get MKL_FAIL__${n}__module)"
        mkl_err0 "    action: $(mkl_var_get MKL_FAIL__${n}__action)"
        mkl_err0 "    reason:
$(mkl_var_get MKL_FAIL__${n}__reason)
"
        # Dig up some metadata to assist the user
        case $MKL_DISTRO in
            debian|ubuntu)
                local debs=$(mkl_meta_get $conf "deb")
                pkg_cmd="sudo apt install -y"
                if [[ ${#debs} > 0 ]]; then
                    install_pkgs="$install_pkgs $debs"
                fi
                ;;
            centos|rhel|redhat|fedora)
                local rpms=$(mkl_meta_get $conf "rpm")
                pkg_cmd="sudo yum install -y"
                if [[ ${#rpms} > 0 ]]; then
                    install_pkgs="$install_pkgs $rpms"
                fi
                ;;
            alpine)
                local apks=$(mkl_meta_get $conf "apk")
                pkg_cmd="apk add "
                if [[ ${#apks} > 0 ]]; then
                    install_pkgs="$install_pkgs $apks"
                fi
                ;;
            osx)
                local pkgs=$(mkl_meta_get $conf "brew")
                pkg_cmd="brew install"
                if [[ ${#pkgs} > 0 ]]; then
                    install_pkgs="$install_pkgs $pkgs"
                fi
                ;;
        esac
    done

    if [[ ! -z $install_pkgs ]]; then
        mkl_err "###########################################################"
        mkl_err "### Installing the following packages might help:       ###"
        mkl_err "###########################################################"
        mkl_err0 "$pkg_cmd $install_pkgs"
        mkl_err0 ""
    fi
    exit 1
}


# Checks if there were failures.
# Returns 0 if there were no failures, else calls failure summary and exits.
function mkl_check_fails {
    if [[ ${#MKL_FAILS} = 0 ]]; then
        return 0
    fi
    mkl_fail_summary
}

# A check has failed but we want to carry on (and we should!).
# We fail it all later.
# Arguments:
#  config name
#  define name
#  action
#  reason
function mkl_fail {
    local n="$(mkl_env_esc "$1")"
    mkl_var_set "MKL_FAIL__${n}__conf" "$1"
    mkl_var_set "MKL_FAIL__${n}__module" $MKL_MODULE
    mkl_var_set "MKL_FAIL__${n}__define" $2
    mkl_var_set "MKL_FAIL__${n}__action" "$3"
    if [[ -z $(mkl_var_get "MKL_FAIL__${n}__reason") ]]; then
        mkl_var_set "MKL_FAIL__${n}__reason" "$4"
    else
        mkl_var_append "MKL_FAIL__${n}__reason" "
And also:
$4"
    fi
    mkl_in_list "$MKL_FAILS" "$n" || mkl_var_append MKL_FAILS "$n"
}


# A check failed, handle it
# Arguments:
#  config name
#  define name
#  action (fail|disable|ignore|cont)
#  reason
function mkl_check_failed {
    # Override action based on require directives, unless the action is
    # set to cont (for fallthrough to sub-sequent tests).
    local action="$3"
    if [[ $3 != "cont" ]]; then
        action=$(mkl_meta_get "MOD__$MKL_MODULE" "override_action" $3)
    fi

    # --fail-fatal option
    [[ $MKL_FAILFATAL ]] && action="fail"

    mkl_check_done "$1" "$2" "$action" "failed"
    mkl_dbg "Check $1 ($2, action $action (originally $3)) failed: $4"


    case $action in
        fail)
            # Check failed fatally, fail everything eventually
            mkl_fail "$1" "$2" "$3" "$4"
            return 1
            ;;

        disable)
            # Check failed, disable
            [[ ! -z $2 ]] && mkl_mkvar_set "$1" "$2" "n"
            return 1
            ;;
        ignore)
            # Check failed but we ignore the results and set it anyway.
            [[ ! -z $2 ]] && mkl_define_set "$1" "$2" "1"
            [[ ! -z $2 ]] && mkl_mkvar_set "$1" "$2" "y"
            return 1
            ;;
        cont)
            # Check failed but we ignore the results and do nothing.
            return 0
            ;;
    esac
}




###########################################################################
#
#
# Output generators
#
#
###########################################################################

# Generate late variables.
# Late variables are those referenced in command line option defaults
# but then never set by --option.
function mkl_generate_late_vars {
    local n
    for n in $MKL_LATE_VARS ; do
        local func=${n%:*}
        local safeopt=${func#opt_}
        local val=${n#*:}
        if mkl_in_list "$MKL_OPTS_SET" "$safeopt" ; then
            # Skip options set explicitly with --option
            continue
        fi
        # Expand variable references "\$foo" by calling eval
        # and pass it opt_... function.
        $func "$(eval echo $val)"
    done
}


# Generate MKL_DYNAMIC_LIBS and MKL_STATIC_LIBS for Makefile.config
#
# Params: $LIBS
function mkl_generate_libs {
    while [[ $# -gt 0 ]]; do
        if [[ $1 == -l* ]]; then
            mkl_mkvar_append "" MKL_DYNAMIC_LIBS $1
        elif [[ $1 == *.a ]]; then
            mkl_mkvar_append "" MKL_STATIC_LIBS $1
        elif [[ $1 == -framework ]]; then
            mkl_mkvar_append "" MKL_DYNAMIC_LIBS "$1 $2"
            shift # two args
        else
            mkl_dbg "Ignoring arg $1 from LIBS while building STATIC and DYNAMIC lists"
        fi
        shift # remove arg
    done
}

# Generate output files.
# Must be called following a succesful configure run.
function mkl_generate {

    # Generate MKL_STATIC_LIBS and MKL_DYNAMIC_LIBS from LIBS
    mkl_generate_libs $LIBS

    local mf=
    for mf in $MKL_GENERATORS ; do
        MKL_MODULE=${mf%:*}
        local func=${mf#*:}
        $func || exit 1
    done

    # Generate a built-in options define based on WITH_..=y
    local with_y=
    for n in $MKL_MKVARS ; do
        if [[ $n == WITH_* ]] && [[ $n != WITH_STATIC_LIB_* ]] && [[ ${!n} == y ]]; then
            with_y="$with_y ${n#WITH_}"
        fi
    done
    with_y="${with_y# }"

    mkl_allvar_set "BUILT_WITH" "BUILT_WITH" "$with_y"

    mkl_write_mk "# Automatically generated by $0 $*"
    mkl_write_mk "# Config variables"
    mkl_write_mk "#"
    mkl_write_mk "# Generated by:"
    mkl_write_mk "# $MKL_CONFIGURE_ARGS"
    mkl_write_mk ""

    # This variable is used by Makefile.base to avoid multiple inclusions.
    mkl_write_mk "MKL_MAKEFILE_CONFIG=y"

    # Export colors to Makefile.config
    mkl_write_mk "MKL_RED=\t${MKL_RED}"
    mkl_write_mk "MKL_GREEN=\t${MKL_GREEN}"
    mkl_write_mk "MKL_YELLOW=\t${MKL_YELLOW}"
    mkl_write_mk "MKL_BLUE=\t${MKL_BLUE}"
    mkl_write_mk "MKL_CLR_RESET=\t${MKL_CLR_RESET}"

    local n=
    for n in $MKL_MKVARS ; do
	# Some special variables should be prefixable by the caller, so
	# define them in the makefile as appends.
	local op="="
	case $n in
	    CFLAGS|CPPFLAGS|CXXFLAGS|LDFLAGS|LIBS)
		op="+="
		;;
	esac
        mkl_write_mk "$n$op\t${!n}"
    done
    mkl_write_mk "# End of config variables"

    MKL_OUTMK_FINAL=Makefile.config
    mv $MKL_OUTMK $MKL_OUTMK_FINAL

    echo "Generated $MKL_OUTMK_FINAL"

    # Generate config.h
    mkl_write_h "// Automatically generated by $0 $*"
    mkl_write_h "#ifndef _CONFIG_H_"
    mkl_write_h "#define _CONFIG_H_"
    for n in $MKL_DEFINES ; do
        mkl_write_h "${!n}"
    done
    mkl_write_h "#endif /* _CONFIG_H_ */"

    MKL_OUTH_FINAL=config.h
    mv $MKL_OUTH $MKL_OUTH_FINAL

    echo "Generated $MKL_OUTH_FINAL"
}

# Remove file noisily, if it exists
function mkl_rm {
    if [[ -f $fname ]]; then
        echo "Removing $fname"
        rm -f "$fname"
    fi
}

# Remove files generated by configure
function mkl_clean {
    for fname in Makefile.config config.h config.cache config.log ; do
        mkl_rm "$fname"
    done

    local mf=
    for mf in $MKL_CLEANERS ; do
        MKL_MODULE=${mf%:*}
        local func=${mf#*:}
        $func || exit 1
    done

}


# Print summary of succesful configure run
function mkl_summary {

    echo "
Configuration summary:"
    local n=
    for n in $MKL_MKVARS ; do
        # Skip the boring booleans
        if [[ $n == ENABLE_* || $n == WITH_* || $n == WITHOUT_* || $n == HAVE_* || $n == def_* ]]; then
            continue
        fi
        printf "  %-24s %s\n" "$n" "${!n}"
    done
}



# Write to mk file
# Argument:
#  string ..
function mkl_write_mk {
    echo -e "$*" >> $MKL_OUTMK
}

# Write to header file
# Argument:
#  string ..
function mkl_write_h {
    echo -e "$*" >> $MKL_OUTH
}



###########################################################################
#
#
# Logging and debugging
#
#
###########################################################################

# Debug print
# Only visible on terminal if MKL_DEBUG is set.
# Always written to config.log
# Argument:
#  string ..
function mkl_dbg {
    if [[ ! -z $MKL_DEBUG ]]; then
        echo -e "${MKL_BLUE}DBG:$$: $*${MKL_CLR_RESET}" 1>&2
    fi
    echo "DBG $$: $*" >> $MKL_OUTDBG
}

# Error print (with color)
# Always printed to terminal and config.log
# Argument:
#  string ..
function mkl_err {
    echo -e "${MKL_RED}$*${MKL_CLR_RESET}" 1>&2
    echo "$*" >> $MKL_OUTDBG
}

# Same as mkl_err but without coloring
# Argument:
#  string ..
function mkl_err0 {
    echo -e "$*" 1>&2
    echo "$*" >> $MKL_OUTDBG
}

# Standard print
# Always printed to terminal and config.log
# Argument:
#  string ..
function mkl_info {
    echo -e "$*" 1>&2
    echo -e "$*" >> $MKL_OUTDBG
}







###########################################################################
#
#
# Misc helpers
#
#
###########################################################################

# Returns the absolute path (but not necesarily canonical) of the first argument
function mkl_abspath {
    echo $1 | sed -e "s|^\([^/]\)|$PWD/\1|"
}

# Returns true (0) if function $1 exists, else false (1)
function mkl_func_exists {
    declare -f "$1" > /dev/null
    return $?
}

# Rename function.
# Returns 0 on success or 1 if old function (origname) was not defined.
# Arguments:
#   origname
#   newname
function mkl_func_rename {
    if ! mkl_func_exists $1 ; then
        return 1
    fi
    local orig=$(declare -f $1)
    local new="$2${orig#$1}"
    eval "$new"
    unset -f "$1"
    return 0
}


# Push module function for later call by mklove.
# The function is renamed to an internal name.
# Arguments:
#  list variable name
#  module name
#  function name
function mkl_func_push {
    local newfunc="__mkl__f_${2}_$(( MKL_IDNEXT++ ))"
    if mkl_func_rename "$3" "$newfunc" ; then
        mkl_var_append "$1" "$2:$newfunc"
    fi
}



# Returns value, or the default string if value is empty.
# Arguments:
#  value
#  default
function mkl_def {
    if [[ ! -z $1 ]]; then
        echo $1
    else
        echo $2
    fi
}


# Render a string (e.g., evaluate its $varrefs)
# Arguments:
#  string
function mkl_render {
    if [[ $* == *\$* ]]; then
        eval "echo $*"
    else
        echo "$*"
    fi
}

# Escape a string so that it becomes suitable for being an env variable.
# This is a destructive operation and the original string cannot be restored.
function mkl_env_esc {
    echo $* | LC_ALL=C sed -e 's/[^a-zA-Z0-9_]/_/g'
}

# Convert arguments to upper case
function mkl_upper {
    echo "$*" | tr '[:lower:]' '[:upper:]'
}

# Convert arguments to lower case
function mkl_lower {
    echo "$*" | tr '[:upper:]' '[:lower:]'
}


# Checks if element is in list
# Arguments:
#   list
#   element
function mkl_in_list {
    local n
    for n in $1 ; do
        [[ $n == $2 ]] && return 0
    done
    return 1
}


# Silent versions of pushd and popd
function mkl_pushd {
    pushd "$1" >/dev/null
}

function mkl_popd {
    popd >/dev/null
}


###########################################################################
#
#
# Cache functionality
#
#
###########################################################################


# Write cache file
function mkl_cache_write {
    [[ ! -z "$MKL_NOCACHE" ]] && return 0
    echo "# mklove configure cache file generated at $(date)" > config.cache
    for n in $MKL_CACHEVARS ; do
        echo "$n=${!n}" >> config.cache
    done
    echo "Generated config.cache"
}


# Read cache file
function mkl_cache_read {
    [[ ! -z "$MKL_NOCACHE" ]] && return 0
    [ -f config.cache ] || return 1

    echo "using cache file config.cache"

    local ORIG_IFS=$IFS
    IFS="$IFS="
    while read -r n v ; do
        [[ -z $n || $n = \#* || -z $v ]] && continue
        # Don't let cache overwrite variables
        [[ -n ${n+r} ]] || mkl_var_set $n $v cache
    done < config.cache
    IFS=$ORIG_IFS
}


###########################################################################
#
#
# Config name meta data
#
#
###########################################################################

# Set metadata for config name
# This metadata is used by mkl in various situations
# Arguments:
#   config name
#   metadata key
#   metadata value (appended)
function mkl_meta_set {
    local metaname="mkl__$1__$2"
    eval "$metaname=\"\$$metaname $3\""
}

# Returns metadata for config name
# Arguments:
#   config name
#   metadata key
#   default (optional)
function mkl_meta_get {
    local metaname="mkl__$1__$2"
    if [[ ! -z ${!metaname} ]]; then
        echo ${!metaname}
    else
        echo "$3"
    fi
}

# Checks if metadata exists
# Arguments:
#   config name
#   metadata key
function mkl_meta_exists {
    local metaname="mkl__$1__$2"
    if [[ ! -z ${!metaname} ]]; then
        return 0
    else
        return 1
    fi
}





###########################################################################
#
#
# Check framework
#
#
###########################################################################


# Print that a check is beginning to run
# Returns 0 if a cached result was used (do not continue with your tests),
# else 1.
#
# If the check should not be cachable then specify argument 3 as "no-cache",
# this is useful when a check not only checks but actually sets config
# variables itself (which is not recommended, but desired sometimes).
#
# Arguments:
#  [ --verb "verb.." ]  (replace "checking for")
#  config name
#  define name
#  action  (fail,cont,disable or no-cache)
#  [ display name ]
function mkl_check_begin {
    local verb="checking for"
    if [[ $1 == "--verb" ]]; then
        verb="$2"
        shift
        shift
    fi

    local name=$(mkl_meta_get $1 name "$4")
    [[ -z $name ]] && name="$1"

    echo -n "$verb $name..."
    if [[ $3 != "no-cache" ]]; then
        local status=$(mkl_var_get "MKL_STATUS_$1")
        # Check cache (from previous run or this one).
        # Only used cached value if the cached check succeeded:
        # it is more likely that a failed check has been fixed than the other
        # way around.
        if [[ ! -z $status && ( $status = "ok" ) ]]; then
            mkl_check_done "$1" "$2" "$3" $status "cached"
            return 0
        fi
    fi
    return 1
}


# Calls the manual_checks function for the given module.
# Use this for modules that provide check hooks that require
# certain call ordering, such as dependent library checks.
#
# Param 1: module name
function mkl_check {
    local modname=$1

    local func="${modname}_manual_checks"
    if ! mkl_func_exists "$func" ; then
        mkl_fail "Check function for module $modname not found: missing mkl_require $modname ?"
        return 1
    fi

    $func
    return $?
}


# Print that a check is done
# Arguments:
#  config name
#  define name
#  action
#  status (ok|failed)
#  extra-info (optional)
function mkl_check_done {
    # Clean up configname to be a safe varname
    local cname=${1//-/_}
    mkl_var_set "MKL_STATUS_$cname" "$4" cache

    mkl_dbg "Setting $1 ($cname) status to $4 (action $3)"

    local extra=""
    if [[ $4 = "failed" ]]; then
        local clr=$MKL_YELLOW
        extra=" ($3)"
        case "$3" in
            fail)
                clr=$MKL_RED
                ;;
            cont)
                extra=""
                ;;
        esac
        echo -e " $clr$4$MKL_CLR_RESET${extra}"
    else
        [[ ! -z $2 ]] && mkl_define_set "$cname" "$2" "1"
        [[ ! -z $2 ]] && mkl_mkvar_set  "$cname" "$2" "y"
        [ ! -z "$5" ] && extra=" ($5)"
        echo -e " $MKL_GREEN$4${MKL_CLR_RESET}$extra"
    fi
}


# Perform configure check by compiling source snippet
# Arguments:
#  [--sub]             (run checker as a sub-check, not doing begin/fail/ok)
#  [--ldflags="..." ]  (appended after "compiler arguments" below)
#  config name
#  define name
#  action (fail|disable)
#  compiler (CC|CXX)
#  compiler arguments (optional "", example: "-lzookeeper")
#  source snippet
function mkl_compile_check {

    local sub=0
    if [[ $1 == --sub ]]; then
        sub=1
        shift
    fi

    local ldf=
    if [[ $1 == --ldflags=* ]]; then
        ldf=${1#*=}
        shift
    fi

    if [[ $sub -eq 0 ]]; then
        mkl_check_begin "$1" "$2" "$3" "$1 (by compile)" && return $?
    fi

    local cflags=

    if [[ $4 = "CXX" ]]; then
        local ext=cpp
        cflags="$(mkl_mkvar_get CXXFLAGS)"
    else
        local ext=c
        cflags="$(mkl_mkvar_get CFLAGS)"
    fi

    local srcfile=$(mktemp _mkltmpXXXXXX)
    mv "$srcfile" "${srcfile}.$ext"
    srcfile="$srcfile.$ext"
    echo "$6" > $srcfile
    echo "
int main () { return 0; }
" >> $srcfile

    local cmd="${!4} $cflags $(mkl_mkvar_get CPPFLAGS) -Wall -Werror $srcfile -o ${srcfile}.o $ldf $(mkl_mkvar_get LDFLAGS) $5 $(mkl_mkvar_get LIBS)";
    mkl_dbg "Compile check $1 ($2) (sub=$sub): $cmd"

    local output
    output=$($cmd 2>&1)

    if [[ $? != 0 ]] ; then
        mkl_dbg "compile check for $1 ($2) failed: $cmd: $output"
        [[ $sub -eq 0 ]] &&  mkl_check_failed "$1" "$2" "$3" "compile check failed:
CC: $4
flags: $5
$cmd:
$output
source: $6"
        local ret=1
    else
        [[ $sub -eq 0 ]] && mkl_check_done "$1" "$2" "$3" "ok"
        local ret=0
    fi

    # OSX XCode toolchain creates dSYM directories when -g is set,
    # delete them specifically.
    rm -rf "$srcfile" "${srcfile}.o" "$srcfile*dSYM"

    return $ret
}


# Low-level: Try to link with a library.
# Arguments:
#  linker flags (e.g. "-lpthreads")
function mkl_link_check0 {
    local libs=$1
    local srcfile=$(mktemp _mktmpXXXXXX)
    echo "#include <stdio.h>
int main () { FILE *fp = stderr; return fp ? 0 : 0; }" > ${srcfile}.c

    local cmd="${CC} $(mkl_mkvar_get CFLAGS) $(mkl_mkvar_get LDFLAGS) ${srcfile}.c -o ${srcfile}_out $libs";
    mkl_dbg "Link check for $1: $cmd"

    local output
    output=$($cmd 2>&1)
    local retcode=$?

    if [[ $retcode -ne 0 ]] ; then
        mkl_dbg "Link check for $1 failed: $output"
    fi

    rm -f $srcfile*
    return $retcode
}


# Try to link with a library.
# Arguments:
#  config name
#  define name
#  action (fail|disable)
#  linker flags (e.g. "-lpthreads")
function mkl_link_check {
    mkl_check_begin "$1" "$2" "$3" "$1 (by linking)" && return $?

    if mkl_link_check0 "$4" ; then
        mkl_check_done "$1" "$2" "$3" "ok" "$4"
        return 0
    else
        mkl_dbg "link check for $1 ($2) failed: $output"
        mkl_check_failed "$1" "$2" "$3" "compile check failed:
$output"
        return 1
    fi
}



# Tries to figure out if we can use a static library or not.
#
# WARNING: This function must not emit any stdout output other than the
#          updated list of libs. Do not use any stdout-printing checker.
#
# Arguments:
#  config name    (e.g., zstd)
#  compiler flags (optional "", e.g: "-lzstd")
# Returns/outputs:
#  New list of compiler flags
function mkl_lib_check_static {
    local configname=$1
    local libs=$2
    local arfile_var=STATIC_LIB_${configname}
    local stfnames=$(mkl_lib_static_fnames $configname)

    mkl_dbg "$configname: Check for static library (libs $libs, arfile variable $arfile_var=${!arfile_var}, static filenames $stfnames)"

    # If STATIC_LIB_<configname> specifies .a file(s) we use that instead.
    if [[ -n ${!arfile_var} ]]; then
        libs="${!arfile_var}"

    elif [[ $WITH_STATIC_LINKING != y ]]; then
        # Static linking not enabled
        echo ""
        return

    elif [[ $HAS_LDFLAGS_STATIC == y ]] && [[ -n $stfnames ]]; then
        local libname
        local stlibs=
        for libname in $stfnames; do
            # Convert the static filename to a linker flag:
            # libzstd.a -> -lzstd
            libname=${libname#lib}
            libname="-l${libname%.a}"
            stlibs="${stlibs}${libname} "
        done
        libs="${LDFLAGS_STATIC} $stlibs ${LDFLAGS_DYNAMIC}"
        mkl_dbg "$configname: after replacing libs: $libs"

    elif [[ $libs == *-L* ]]; then
        # Try to resolve full static paths using any -Lpaths in $libs
        local lpath
        for lpath in $libs; do
            [[ $lpath == -L* ]] || continue

            lpath="${lpath#-L}"
            [[ -d $lpath ]] || continue

            if mkl_resolve_static_libs "$configname" "$lpath"; then
                break
            fi
        done

        libs="${!arfile_var}"
        mkl_dbg "$configname: after -L resolve, libs is $libs"

    else
        mkl_dbg "$configname: Neither $arfile_var=/path/to/libname.a specified nor static linker flags supported: static linking probably won't work"
        libs=""
    fi

    if [[ -z $libs ]]; then
        echo ""
        return
    fi

    # Attempt to link a small program with these static libraries
    mkl_dbg "$configname: verifying that linking \"$libs\" works"
    if ! mkl_link_check0 "$libs" ; then
        mkl_dbg "$configname: Could not use static libray flags: $libs"
        echo ""
        return
    fi

    mkl_allvar_set "$configname" "${configname}_STATIC" "y"

    echo $libs
}


# Checks that the specified lib is available through a number of methods.
# compiler flags are automatically appended to "LIBS" mkvar on success.
#
# If STATIC_LIB_<libname_without_-l> is set to the path of an <libname>.a file
# it will be used instead of -l<libname>.
#
# <definename>_STATIC will be automatically defined (for both Makefile.config
# and config.h) if the library is to be linked statically, or was installed
# with a source dependency installer.
#
# Arguments:
#  [--override-action=<action>]  (internal use, overrides action argument)
#  [--no-static]  (do not attempt to link the library statically)
#  [--libname=<lib>] (library name if different from config name, such as
#                     when the libname includes a dash)
#  config name (library name (for pkg-config))
#  define name
#  action (fail|disable|cont)
#  compiler (CC|CXX)
#  compiler flags (optional "", e.g: "-lyajl")
#  source snippet
function mkl_lib_check0 {

    local override_action=
    local nostaticopt=
    local libnameopt=
    local libname=

    while [[ $1 == --* ]]; do
        if [[ $1 == --override-action=* ]]; then
            override_action=${1#*=}
        elif [[ $1 == --no-static ]]; then
            nostaticopt=$1
        elif [[ $1 == --libname* ]]; then
            libnameopt=$1
            libname="${libnameopt#*=}"
        else
            mkl_err "mkl_lib_check: invalid option $1"
            exit 1
        fi
        shift
    done

    if [[ -z $libname ]]; then
        libname=$1
    fi

    local action=$3
    if [[ -n $override_action ]]; then
        action=$override_action
    fi

    # pkg-config result (0=ok)
    local pkg_conf_failed=1
    if [[ $WITH_PKGCONFIG == "y" ]]; then
        # Let pkg-config populate CFLAGS, et.al.
        # Return on success.
        mkl_pkg_config_check $nostaticopt $libnameopt "$1" "$2" cont "$4" "$6" && return $?
    fi

    local libs="$5"
    local is_static=0

    if [[ -z $nostaticopt ]]; then
        local stlibs=$(mkl_lib_check_static $1 "$libs")
        if [[ -n $stlibs ]]; then
            libs=$stlibs
            is_static=1
        fi
    fi

    if ! mkl_compile_check "$1" "$2" "$action" "$4" "$libs" "$6"; then
        return 1
    fi

    if [[ -n $libs ]]; then
        # Add libraries in reverse order to make sure inter-dependencies
        # are resolved in the correct order.
        # E.g., check for crypto and then ssl should result in -lssl -lcrypto
        mkl_dbg "$1: from lib_check: LIBS: prepend $libs"
        mkl_mkvar_prepend "$1" LIBS "$libs"
        if [[ $is_static == 0 ]]; then
            # Static libraries are automatically bundled with
            # librdkafka-static.a so there is no need to add them as an
            # external linkage dependency.
            mkl_mkvar_prepend "$1" MKL_PKGCONFIG_LIBS_PRIVATE "$libs"
        fi
    fi

    return 0
}


# Wrapper for mkl_lib_check0 which attempts dependency installation
# if --install-deps is specified.
#
# See mkl_lib_check0 for arguments and details.
function mkl_lib_check {

    local arg=
    local name=

    # Find config name parameter (first non-option (--...))
    for arg in $* ; do
        if [[ $arg == --* ]]; then
            continue
        fi
        name=$arg
        break
    done

    if [[ $MKL_INSTALL_DEPS != y ]] || ! mkl_dep_has_installer "$name" ; then
        mkl_lib_check0 "$1" "$2" "$3" "$4" "$5" "$6" "$7" "$8"
        return $?
    fi


    # Automatic dependency installation mode:
    # First pass is lib check with cont,
    # if it fails, attempt dependency installation,
    # and then make second with caller's fail-action.

    local retcode=

    # With --source-deps-only we want to make sure the dependency
    # being used is in-fact from the dependency builder (if supported),
    # rather than a system installed alternative, so skip the pre-check and
    # go directly to dependency installation/build below.
    if [[ $MKL_SOURCE_DEPS_ONLY != y ]] || ! mkl_dep_has_builder $name ; then
        mkl_lib_check0 --override-action=cont "$1" "$2" "$3" "$4" "$5" "$6" "$7" "$8"
        retcode=$?
        if [[ $retcode -eq 0 ]]; then
            # Successful on first pass
            return $retcode
        fi
    else
        mkl_dbg "$name: skipping dependency pre-check in favour of --source-deps-only"
    fi

    # Install dependency
    if ! mkl_dep_install "$name" ; then
        return 1
    fi

    # Second pass: check again, this time fail hard
    mkl_lib_check0 --override-action=fail "$1" "$2" "$3" "$4" "$5" "$6" "$7" "$8"
    return $?
}



# Check for library with pkg-config
# Automatically sets CFLAGS and LIBS from pkg-config information.
# Arguments:
#  [--no-static]  (do not attempt to link the library statically)
#  [--libname=<lib>] (library name if different from config name, such as
#                     when the libname includes a dash)
#  config name
#  define name
#  action (fail|disable|ignore|cont)
#  compiler (CC|CXX)
#  source snippet
function mkl_pkg_config_check {

    local nostaticopt=
    if [[ $1 == --no-static ]]; then
        nostaticopt=$1
        shift
    fi

    local libname=$1
    if [[ $1 == --libname* ]]; then
        libname="${libnameopt#*=}"
        shift
    fi

    local cname="${1}_PKGCONFIG"
    mkl_check_begin "$cname" "$2" "no-cache" "$1 (by pkg-config)" && return $?

    local cflags=
    local cmd="${PKG_CONFIG} --short-errors --cflags $libname"
    mkl_dbg "pkg-config check $libname for CFLAGS ($2): $cmd"

    cflags=$($cmd 2>&1)
    if [[ $? != 0 ]]; then
        mkl_dbg "'$cmd' failed: $cflags"
        # Clear define name ($2): caller may have additional checks
        mkl_check_failed "$cname" "" "$3" "'$cmd' failed:
$cflags"
        return 1
    fi

    if [[ $(mkl_meta_get $1 installed_with) == "source" && \
              $WITH_STATIC_LINKING == y && \
              $MKL_SOURCE_DEPS_ONLY == y ]]; then
        # If attempting static linking and we're using source-only
        # dependencies, then there is no need for pkg-config since
        # the source installer will have set the required flags.
        mkl_check_failed "$cname" "" "ignore" "pkg-config ignored for static build"
        return 1
    fi

    local libs=
    cmd="${PKG_CONFIG} --short-errors --libs $libname"
    mkl_dbg "pkg-config check $libname for LIBS ($2): $cmd"
    libs=$($cmd 2>&1)
    if [[ $? != 0 ]]; then
        mkl_dbg "${PKG_CONFIG} --libs $libname failed: $libs"
        # Clear define name ($2): caller may have additional checks
        mkl_check_failed "$cname" "" "$3" "pkg-config --libs failed"
        return 1
    fi

    mkl_dbg "$1: from pkg-config: CFLAGS '$CFLAGS', LIBS '$LIBS'"

    local snippet="$5"
    if [[ -n $snippet ]]; then
        mkl_dbg "$1: performing compile check using pkg-config info"

        if ! mkl_compile_check --sub "$1" "$2" "no-cache" "$4" "$cflags $libs" "$snippet"; then
            mkl_check_failed "$cname" "" "$3" "compile check failed"
            return 1
        fi
    fi

    mkl_mkvar_append $1 "MKL_PKGCONFIG_REQUIRES_PRIVATE" "$libname"

    mkl_mkvar_append $1 "CFLAGS" "$cflags"

    if [[ -z $nostaticopt ]]; then
        local stlibs=$(mkl_lib_check_static $1 "$libs")
        if [[ -n $stlibs ]]; then
            libs=$stlibs
        else
            # if we don't find a static library to bundle into the
            # -static.a, we need to export a pkgconfig dependency
            # so it can be resolved when linking downstream packages
            mkl_mkvar_append $1 "MKL_PKGCONFIG_REQUIRES" "$libname"
        fi
    fi

    mkl_dbg "$1: from pkg-config: LIBS: prepend $libs"
    mkl_mkvar_prepend "$1" LIBS "$libs"

    mkl_check_done "$1" "$2" "$3" "ok"

    return 0
}


# Check that a command runs and exits succesfully.
# Arguments:
#  config name
#  define name (optional, can be empty)
#  action
#  command
function mkl_command_check {
    mkl_check_begin "$1" "$2" "$3" "$1 (by command)" && return $?

    local out=
    out=$($4 2>&1)
    if [[ $? != 0 ]]; then
        mkl_dbg "$1: $2: $4 failed: $out"
        mkl_check_failed "$1" "$2" "$3" "command '$4' failed:
$out"
        return 1
    fi

    mkl_check_done "$1" "$2" "$3" "ok"

    return 0
}


# Check that a program is executable, but will not execute it.
# Arguments:
#  config name
#  define name (optional, can be empty)
#  action
#  program name  (e.g, objdump)
function mkl_prog_check {
    mkl_check_begin --verb "checking executable" "$1" "$2" "$3" "$1" && return $?

    local out=
    out=$(command -v "$4" 2>&1)
    if [[ $? != 0 ]]; then
        mkl_dbg "$1: $2: $4 is not executable: $out"
        mkl_check_failed "$1" "$2" "$3" "$4 is not executable"
        return 1
    fi

    mkl_check_done "$1" "$2" "$3" "ok"

    return 0
}




# Checks that the check for the given config name passed.
# This does not behave like the other checks, if the given config name passed
# its test then nothing is printed. Else the configure will fail.
# Arguments:
#  checked config name
function mkl_config_check {
    local status=$(mkl_var_get "MKL_STATUS_$1")
    [[ $status = "ok" ]] && return 0
    mkl_fail $1 "" "fail" "$MKL_MODULE requires $1"
    return 1
}


# Checks that all provided config names are set.
# Arguments:
#  config name
#  define name
#  action
#  check_config_name1
#  check_config_name2..
function mkl_config_check_all {
    local cname=
    local res="ok"
    echo start this now for $1
    for cname in ${@:4}; do
        local st=$(mkl_var_get "MKL_STATUS_$cname")
        [[ $status = "ok" ]] && continue
        mkl_fail $1 $2 $3 "depends on $cname"
        res="failed"
    done

    echo "try res $res"
    mkl_check_done "$1" "$2" "$3" $res
}


# Check environment variable
# Arguments:
#  config name
#  define name
#  action
#  environment variable
function mkl_env_check {
    mkl_check_begin "$1" "$2" "$3" "$1 (by env $4)" && return $?

    if [[ -z ${!4} ]]; then
        mkl_check_failed "$1" "$2" "$3" "environment variable $4 not set"
        return 1
    fi

    mkl_check_done "$1" "$2" "$3" "ok" "${!4}"

    return 0
}


# Run all checks
function mkl_checks_run {
    # Set up common variables
    mkl_allvar_set "" MKL_APP_NAME $(mkl_meta_get description name)
    mkl_allvar_set "" MKL_APP_DESC_ONELINE "$(mkl_meta_get description oneline)"

    # Call checks functions in dependency order
    local mf
    for mf in $MKL_CHECKS ; do
        MKL_MODULE=${mf%:*}
        local func=${mf#*:}

        if mkl_func_exists $func ; then
            $func
        else
            mkl_err "Check function $func from $MKL_MODULE disappeared ($mf)"
        fi
        unset MKL_MODULE
    done
}


# Check for color support in terminal.
# If the terminal supports colors, the function will alter
#  MKL_RED
#  MKL_GREEN
#  MKL_YELLOW
#  MKL_BLUE
#  MKL_CLR_RESET
function mkl_check_terminal_color_support {
    local use_color=false
    local has_tput=false

    if [[ -z ${TERM} ]]; then
        # tput and dircolors require $TERM
        mkl_dbg "\$TERM is not set! Cannot check for color support in terminal."
        return 1
    elif hash tput 2>/dev/null; then
        has_tput=true
        [[ $(tput colors 2>/dev/null) -ge 8 ]] && use_color=true
        mkl_dbg "tput reports color support: ${use_color}"
    elif hash dircolors 2>/dev/null; then
        # Enable color support only on colorful terminals.
        # dircolors --print-database uses its own built-in database
        # instead of using /etc/DIR_COLORS. Try to use the external file
        # first to take advantage of user additions.
        local safe_term=${TERM//[^[:alnum:]]/?}
        local match_lhs=""
        [[ -f ~/.dir_colors   ]] && match_lhs="${match_lhs}$(<~/.dir_colors)"
        [[ -f /etc/DIR_COLORS ]] && match_lhs="${match_lhs}$(</etc/DIR_COLORS)"
        [[ -z ${match_lhs}    ]] && match_lhs=$(dircolors --print-database)
        [[ $'\n'${match_lhs} == *$'\n'"TERM "${safe_term}* ]] && use_color=true
        mkl_dbg "dircolors reports color support: ${use_color}"
    fi

    if ${use_color}; then
        if ${has_tput}; then
            # In theory, user could have set different escape sequences
            # Because tput is available we can use it to query the right values ...
            mkl_dbg "Using color escape sequences from tput"
            MKL_RED=$(tput setaf 1)
            MKL_GREEN=$(tput setaf 2)
            MKL_YELLOW=$(tput setaf 3)
            MKL_BLUE=$(tput setaf 4)
            MKL_CLR_RESET=$(tput sgr0)
        else
            mkl_dbg "Using hard-code ANSI color escape sequences"
            MKL_RED="\033[031m"
            MKL_GREEN="\033[032m"
            MKL_YELLOW="\033[033m"
            MKL_BLUE="\033[034m"
            MKL_CLR_RESET="\033[0m"
        fi
    else
        mkl_dbg "Did not detect color support in \"$TERM\" terminal!"
    fi

    return 0
}




###########################################################################
#
#
# Module functionality
#
#
###########################################################################

# Downloads module from repository.
# Arguments:
#  module name
# Returns:
#  module file name
function mkl_module_download {
    local modname="$1"
    local url="$MKL_REPO_URL/modules/configure.$modname"
    local tmpfile=""

    fname="${MKLOVE_DIR}/modules/configure.$modname"

    if [[ $url != http*://* ]]; then
        # Local path, just copy file.
        if [[ ! -f $url ]]; then
            mkl_err "Module $modname not found at $url"
            return 1
        fi

        if ! cp "$url" "$fname" ; then
            mkl_err "Failed to copy $url to $fname"
            return 1
        fi

        echo "$fname"
        return 0
    fi

    # Download
    mkl_info "${MKL_BLUE}downloading missing module $modname from $url${MKL_CLR_RESET}"

    tmpfile=$(mktemp _mkltmpXXXXXX)
    local out=
    out=$(curl -fLs -o "$tmpfile" "$url" 2>&1)

    if [[ $? -ne 0 ]]; then
        rm -f "$tmpfile"
        mkl_err "Failed to download $modname:"
        mkl_err0 $out
        return 1
    fi

    # Move downloaded file into place replacing the old file.
    mv "$tmpfile" "$fname" || return 1

    # "Return" filename
    echo "$fname"

    return 0
}


# Load module by name or filename
# Arguments:
#   "require"|"try"
#   filename
# [ module arguments ]
function mkl_module_load {
    local try=$1
    shift
    local fname=$1
    shift
    local modname=${fname#*configure.}
    local bypath=1

    # Check if already loaded
    if mkl_in_list "$MKL_MODULES" "$modname"; then
        return 0
    fi

    if [[ $fname = $modname ]]; then
        # Module specified by name, find the file.
        bypath=0
        for fname in configure.$modname \
            ${MKLOVE_DIR}/modules/configure.$modname ; do
            [[ -s $fname ]] && break
        done
    fi

    # Calling module
    local cmod=$MKL_MODULE
    [[ -z $cmod ]] && cmod="base"

    if [[ ! -s $fname ]]; then
        # Attempt to download module, if permitted
        if [[ $MKL_NO_DOWNLOAD != 0 || $bypath == 1 ]]; then
            mkl_err "Module $modname not found at $fname (required by $cmod) and downloads disabled"
            if [[ $try = "require" ]]; then
                mkl_fail "$modname" "none" "fail" \
                    "Module $modname not found (required by $cmod) and downloads disabled"
            fi
            return 1
        fi

        fname=$(mkl_module_download "$modname")
        if [[ $? -ne 0 ]]; then
            mkl_err "Module $modname not found (required by $cmod)"
            if [[ $try = "require" ]]; then
                mkl_fail "$modname" "none" "fail" \
                    "Module $modname not found (required by $cmod)"
                return 1
            fi
        fi

        # Now downloaded, try loading the module again.
        mkl_module_load $try "$fname" "$@"
        return $?
    fi

    # Set current module
    local save_MKL_MODULE=$MKL_MODULE
    MKL_MODULE=$modname

    mkl_dbg "Loading module $modname (required by $cmod) from $fname"

    # Source module file (positional arguments are available to module)
    source $fname

    # Restore current module (might be recursive)
    MKL_MODULE=$save_MKL_MODULE

    # Add module to list of modules
    mkl_var_append MKL_MODULES $modname

    # Rename module's special functions so we can call them separetely later.
    mkl_func_rename "options" "${modname}_options"
    mkl_func_rename "install_source" "${modname}_install_source"
    mkl_func_rename "manual_checks" "${modname}_manual_checks"
    mkl_func_push MKL_CHECKS "$modname" "checks"
    mkl_func_push MKL_GENERATORS "$modname" "generate"
    mkl_func_push MKL_CLEANERS "$modname" "clean"
}


# Require and load module
# Must only be called from module file outside any function.
# Arguments:
#  [ --try ]    Dont fail if module doesn't exist
#  module1
#  [ "must" "pass" ]
#  [ module arguments ... ]
function mkl_require {
    local try="require"
    if [[ $1 = "--try" ]]; then
        local try="try"
        shift
    fi

    local mod=$1
    shift
    local override_action=

    # Check for cyclic dependencies
    if mkl_in_list "$MKL_LOAD_STACK" "$mod"; then
        mkl_err "Cyclic dependency detected while loading $mod module:"
        local cmod=
        local lmod=$mod
        for cmod in $MKL_LOAD_STACK ; do
            mkl_err "  $lmod required by $cmod"
            lmod=$cmod
        done
        mkl_fail base "" fail "Cyclic dependency detected while loading module $mod"
        return 1
    fi

    mkl_var_prepend MKL_LOAD_STACK "$mod"


    if [[ "$1 $2" == "must pass" ]]; then
        shift
        shift
        override_action="fail"
    fi

    if [[ ! -z $override_action ]]; then
        mkl_meta_set "MOD__$mod" "override_action" "$override_action"
    fi


    mkl_module_load $try $mod "$@"
    local ret=$?

    mkl_var_shift MKL_LOAD_STACK

    return $ret
}



###########################################################################
#
#
# Usage options
#
#
###########################################################################


MKL_USAGE="Usage: ./configure [OPTIONS...]

 mklove configure script - mklove, not autoconf
 Copyright (c) 2014-2019 Magnus Edenhill - https://github.com/edenhill/mklove
"

function mkl_usage {
    echo "$MKL_USAGE"
    local name=$(mkl_meta_get description name)

    if [[ ! -z ${name} ]]; then
	echo " $name - $(mkl_meta_get description oneline)
 $(mkl_meta_get description copyright)
"
    fi

    local og
    for og in $MKL_USAGE_GROUPS ; do
        og="MKL_USAGE_GROUP__$og"
        echo "${!og}"
    done

    echo "Honoured environment variables:
  CC, CPP, CXX, CFLAGS, CPPFLAGS, CXXFLAGS, LDFLAGS, LIBS,
  LD, NM, OBJDUMP, STRIP, RANLIB, PKG_CONFIG, PKG_CONFIG_PATH,
  STATIC_LIB_<libname>=.../libname.a

"

}



# Add usage option informative text
# Arguments:
#  text
function mkl_usage_info {
    MKL_USAGE="$MKL_USAGE
$1"
}


# Add option to usage output
# Arguments:
#  option group ("Standard", "Cross-Compilation", etc..)
#  variable name
#  option ("--foo", "--foo=*", "--foo=args_required")
#  help
#  default (optional)
#  assignvalue (optional, default:"y")
#  function block (optional)
#
# If option takes the form --foo=* then arguments are optional.
function mkl_option {
    local optgroup=$1
    local varname=$2

    # Fixed width between option name and help in usage output
    local pad="                                   "
    if [[ ${#3} -lt ${#pad} ]]; then
        pad=${pad:0:$(expr ${#pad} - ${#3})}
    else
        pad=""
    fi

    # Add to usage output
    local optgroup_safe=$(mkl_env_esc $optgroup)
    if ! mkl_in_list "$MKL_USAGE_GROUPS" "$optgroup_safe" ; then
        mkl_env_append MKL_USAGE_GROUPS "$optgroup_safe"
        mkl_env_set "MKL_USAGE_GROUP__$optgroup_safe" "$optgroup options:
"
    fi

    local defstr=""
    [[ ! -z $5 ]] && defstr=" [$5]"
    mkl_env_append "MKL_USAGE_GROUP__$optgroup_safe" "  $3 $pad $4$defstr
"

    local optname="${3#--}"
    local safeopt=
    local optval=""
    if [[ $3 == *=* ]]; then
        optname="${optname%=*}"
        optval="${3#*=}"
        if [[ $optval == '*' ]]; then
            # Avoid globbing of --foo=* optional arguments
            optval='\*'
        fi
    fi

    safeopt=$(mkl_env_esc $optname)

    mkl_meta_set "MKL_OPT_ARGS" "$safeopt" "$optval"

    #
    # Optional variable scoping by prefix: "env:", "mk:", "def:"
    #
    local setallvar="mkl_allvar_set ''"
    local setmkvar="mkl_mkvar_set ''"

    if [[ $varname = env:* ]]; then
        # Set environment variable (during configure runtime only)
        varname=${varname#*:}
        setallvar=mkl_env_set
        setmkvar=mkl_env_set
    elif [[ $varname = mk:* ]]; then
        # Set Makefile.config variable
        varname=${varname#*:}
        setallvar="mkl_mkvar_append ''"
        setmkvar="mkl_mkvar_append ''"
    elif [[ $varname = def:* ]]; then
        # Set config.h define
        varname=${varname#*:}
        setallvar="mkl_define_set ''"
        setmkvar="mkl_define_set ''"
    fi


    if [[ ! -z $7 ]]; then
        # Function block specified.
        eval "function opt_$safeopt { $7 }"
    else
    # Add default implementation of function simply setting the value.
    # Application may override this by redefining the function after calling
    # mkl_option.
        if [[ $optval = "PATH" ]]; then
        # PATH argument: make it an absolute path.
        # Only set the make variable (not config.h)
            eval "function opt_$safeopt { $setmkvar $varname \"\$(mkl_abspath \$(mkl_render \$1))\"; }"
        else
        # Standard argument: simply set the value
            if [[ -z "$6" ]]; then
                eval "function opt_$safeopt { $setallvar $varname \"\$1\"; }"
            else
                eval "function opt_$safeopt { $setallvar $varname \"$6\"; }"
            fi
        fi
    fi

    # If default value is provided and does not start with "$" (variable ref)
    # then set it right away.
    # $ variable refs are set after all checks have run during the
    # generating step.
    if [[ ${#5} != 0 ]] ; then
        if [[ $5 = *\$* ]]; then
            mkl_var_append "MKL_LATE_VARS" "opt_$safeopt:$5"
        else
            opt_$safeopt $5
        fi
    fi

    if [[ ! -z $varname ]]; then
        # Add variable to list
        MKL_CONFVARS="$MKL_CONFVARS $varname"
    fi

}



# Adds a toggle (--enable-X, --disable-X) option.
# Arguments:
#  option group   ("Standard", ..)
#  variable name  (WITH_FOO)
#  option         (--enable-foo, --enable-foo=*, or --enable-foo=req)
#  help           ("foo.." ("Enable" and "Disable" will be prepended))
#  default        (y or n)

function mkl_toggle_option {

    # Add option argument
    mkl_option "$1" "$2" "$3" "$4" "$5"

    # Add corresponding "--disable-foo" option for "--enable-foo".
    local disname="${3/--enable/--disable}"
    local dishelp="${4/Enable/Disable}"
    mkl_option "$1" "$2" "$disname" "$dishelp" "" "n"
}

# Adds a toggle (--enable-X, --disable-X) option with builtin checker.
# This is the library version.
# Arguments:
#  option group   ("Standard", ..)
#  config name    (foo, must be same as pkg-config name)
#  variable name  (WITH_FOO)
#  action         (fail or disable)
#  option         (--enable-foo)
#  help           (defaults to "Enable <config name>")
#  linker flags   (-lfoo)
#  default        (y or n)

function mkl_toggle_option_lib {

    local help="$6"
    [[ -z "$help" ]] && help="Enable $2"

    # Add option argument
    mkl_option "$1" "$3" "$5" "$help" "$8"

    # Add corresponding "--disable-foo" option for "--enable-foo".
    local disname="${5/--enable/--disable}"
    local dishelp="${help/Enable/Disable}"
    mkl_option "$1" "$3" "$disname" "$dishelp" "" "n"

    # Create checks
    eval "function _tmp_func { mkl_lib_check \"$2\" \"$3\" \"$4\" CC \"$7\"; }"
    mkl_func_push MKL_CHECKS "$MKL_MODULE" _tmp_func
}



# Downloads, verifies checksum, and extracts an archive to
# the current directory.
#
# Arguments:
#  url       Archive URL
#  shabits  The SHA algorithm bit count used to verify the checksum. E.g., "256".
#  checksum  Expected checksum of archive (use "" to not perform check)
function mkl_download_archive {
    local url="$1"
    local shabits="$2"
    local exp_checksum="$3"

    local tmpfile=$(mktemp _mkltmpXXXXXX)

    # Try both wget and curl
    if ! wget -nv -O "$tmpfile" "$url" ; then
        if ! curl -fLsS -o "$tmpfile" "$url" ; then
            rm -f "$tmpfile"
            echo -e "ERROR: Download of $url failed" 1>&2
            return 1
        fi
    fi

    if [[ -n $exp_checksum ]]; then
        # Verify checksum

        local checksum_tool=""

        # OSX has shasum by default, on Linux it is typically in
        # some Perl package that may or may not be installed.
        if $(which shasum >/dev/null 2>&1); then
            checksum_tool="shasum -b -a ${shabits}"
        else
            # shaXsum is available in Linux coreutils
            checksum_tool="sha${shabits}sum"
        fi

        local checksum=$($checksum_tool "$tmpfile" | cut -d' ' -f1)
        if [[ $? -ne 0 ]]; then
            rm -f "$tmpfile"
            echo "ERROR: Failed to verify checksum of $url with $checksum_tool" 1>&2
            return 1
        fi

        if [[ $checksum != $exp_checksum ]]; then
            rm -f "$tmpfile"
            echo "ERROR: $url: $checksum_tool: Checksum mismatch: expected $exp_checksum, calculated $checksum" 1>&2
            return 1
        fi

        echo "### Checksum of $url verified ($checksum_tool):"
        echo "###  Expected:   $exp_checksum"
        echo "###  Calculated: $checksum"
    fi

    tar xzf "$tmpfile" --strip-components 1
    if [[ $? -ne 0 ]]; then
        rm -f "$tmpfile"
        echo "ERROR: $url: failed to extract archive" 1>&2
        return 1
    fi


    rm -f "$tmpfile"
    return 0
}
