devtools/bin/find_m4.sh

#!/bin/sh

# Copyright (c) 1998-2001 Proofpoint, Inc. and its suppliers.
#   All rights reserved.
#
# By using this file, you agree to the terms and conditions set
# forth in the LICENSE file which can be found at the top level of
# the sendmail distribution.
#
#
#       $Id: find_m4.sh,v 8.14 2013-11-22 20:51:24 ca Exp $
#

# Try to find a working M4 program.
# If $M4 is already set, we use it, otherwise we prefer GNU m4.

EX_UNAVAILABLE=69

test="ifdef(\`pushdef', \`',
\`errprint(\`You need a newer version of M4, at least as new as System V or GNU')
include(NoSuchFile)')
define(\`BadNumber', \`10')
ifdef(\`BadNumber', \`',
\`errprint(\`This version of m4 is broken: trailing zero problem')
include(NoSuchFile)')
define(\`LongList', \` assert.c debug.c exc.c heap.c match.c rpool.c strdup.c strerror.c strl.c clrerr.c fclose.c feof.c ferror.c fflush.c fget.c fpos.c findfp.c flags.c fopen.c fprintf.c fpurge.c fput.c fread.c fscanf.c fseek.c fvwrite.c fwalk.c fwrite.c get.c makebuf.c put.c refill.c rewind.c rget.c setvbuf.c smstdio.c snprintf.c sscanf.c stdio.c strio.c syslogio.c ungetc.c vasprintf.c vfprintf.c vfscanf.c vprintf.c vsnprintf.c vsprintf.c vsscanf.c wbuf.c wsetup.c stringf.c xtrap.c strto.c test.c path.c strcasecmp.c signal.c clock.c config.c shm.c ')
define(\`SameList', \`substr(LongList, 0, index(LongList, \`.'))\`'substr(LongList, index(LongList, \`.'))')
ifelse(len(LongList), len(SameList), \`',
\`errprint(\`This version of m4 is broken: length problem')
include(NoSuchFile)')"

if [ "$M4" ]
then
    err="`(echo "$test" | $M4) 2>&1 >/dev/null`"
    code=$?
else
    firstfound=
    ifs="$IFS"; IFS="${IFS}:"
    for m4 in gm4 gnum4 pdm4 m4
    do
        for dir in $PATH /usr/5bin /usr/ccs/bin
        do
            [ -z "$dir" ] && dir=.
            if [ -f $dir/$m4 ]
            then
                err="`(echo "$test" | $dir/$m4) 2>&1 >/dev/null`"
                ret=$?
                if [ $ret -eq 0 -a "X$err" = "X" ]
                then
                    M4=$dir/$m4
                    code=0
                    break
                else
                    case "$firstfound:$err" in
                      :*version\ of*)
                        firstfound=$dir/$m4
                        firsterr="$err"
                        firstcode=$ret
                        ;;
                    esac
                fi
            fi
        done
        [ "$M4" ] && break
    done
    IFS="$ifs"
    if [ ! "$M4" ]
    then
        if [ "$firstfound" ]
        then
            M4=$firstfound
            err="$firsterr"
            code=$firstcode
        else
            echo "ERROR: Can not locate an M4 program" >&2
            exit $EX_UNAVAILABLE
        fi
    fi
fi
if [ $code -ne 0 ]
then
    echo "ERROR: Using M4=$M4: $err" | grep -v NoSuchFile >&2
    exit $EX_UNAVAILABLE
elif [ "X$err" != "X" ]
then
    echo "WARNING: $err" >&2
fi
echo $M4
exit 0