configure

#! /bin/sh -
#
# configure script for wak (awk implementation)
#
# This script writes a Makefile for wak, allowing
# a little control over 'prefix', 'CC', 'CFLAGS'

# For security
IFS='
 	'
OLDPATH="$PATH"
PATH=/bin:/usr/bin
export PATH

version='wak configure 24.10 20241008'

# Default values
prefix=${prefix-/usr/local}
CC=${CC-gcc}
CFLAGS=${CFLAGS--O3 -funsigned-char -std=c99 -Wall -Wextra -W -Wpointer-arith -Wstrict-prototypes -D_POSIX_C_SOURCE=200809L }

help() {
    echo "'configure' configures $version"
    echo
    echo Usage: ./configure [OPTION]... [VAR=VALUE]...
    echo
    echo 'To assign environment variables (e.g., CC, CFLAGS...), specify them as'
    echo VAR=VALUE, e.g. \'CC=clang\'
    echo
    echo Option defaults are shown in brackets.
    echo
    echo Configuration:
    echo '  -h, --help              display this help and exit'
    echo '  -V, --version           display version information and exit'
    echo
    echo Installation directory:
    echo '  --prefix=PREFIX        install architecture-independent files in PREFIX'
    echo '                         [/usr/local]'
    echo \'make install\' will install to /usr/local/bin etc. by default.
    echo Use e.g. \'--prefix=\$HOME\' to change this.
    echo
    echo   with no options, configure these defaults:
    show_defaults
    exit 0
}

show_defaults() {
    echo prefix=${prefix-/usr/local}
    echo CC=${CC-gcc}
    echo CFLAGS=${CFLAGS--O3 -funsigned-char -std=c99 -Wall -Wextra -W -Wpointer-arith -Wstrict-prototypes -D_POSIX_C_SOURCE=200809L }
}

error() {
    echo "$@" 1>&2
    exit 1
}

check_eq_arg() {
    # Ensure exactly one = sign, non-empty optval
    if [ x${arg##*=*=} != x${arg} ] || [ x${arg##*=} = x${arg} ] || [ -z $optval ]
    then
        error 'Bad arg:' ${arg}
    fi
}

make_makefile() {
    sed -e "s?@prefix@?${prefix}?g"   \
        -e "s?@CC@?${CC}?g"           \
        -e "s?@CFLAGS@?${CFLAGS}?g"   \
        < Makefile.in > Makefile
}

if [ $# = 0 ]
then
    echo 'No args; using this config (--help to show options):'
    show_defaults
    make_makefile
    exit 0
fi

while [ $# != 0 ]
do
    arg=$1
    option=${arg%=*} # arg up to an = (if any)
    optval=${arg#*=} # arg following = (if any)
    if [ -z $option ]
    then
        error 'Bad arg:' $1
    fi
    case $option in
        '--?' | '-?' | --h | --he | --hel | --help | -h | -he | -hel | -help)
            help
            ;;
        --v | --ve | --ver | --vers | --versi | --versio | --version | -v | -ve | -ver | -vers | -versi | -versio | -version | -V)
            echo $version
            exit 0
            ;;
        '--prefix')
            check_eq_arg
            prefix=$optval
            ;;
        'CC')
            check_eq_arg
            CC=$optval
            ;;
        'CFLAGS')
            check_eq_arg
            CFLAGS=$optval
            ;;
        -*)
            error Bad option arg: $1
            ;;
        *)
            error Bad arg: $1
            ;;
    esac
    shift
done

make_makefile

exit 0