#!/bin/sh
#
# Minimal Make-Pre-Processor.
# Provided to cope with trying to use my makefiles
# on systems which don't have GNU make installed.
# Supports ifdef,ifndef,else and endif's, nested.
#

if [ "$1" = "" ] ; then
	echo "usage: mpp makefile {SYMBOL}"
	exit
fi

file=$1
shift

if [ `uname -s` = SunOS ] ; then
	awk=nawk
else
	awk=awk
fi

$awk ' \
BEGIN	{ l=1 ; e[1]=1 ; } \
	{ \
	     if ( $1 == "ifdef"  ) { ++l ; e[l]=e[l-1]&& defined($2) ; } \
	else if ( $1 == "ifndef" ) { ++l ; e[l]=e[l-1]&&!defined($2) ; } \
	else if ( $1 == "else"   )         e[l]=e[l-1]&&!e[l]        ;   \
	else if ( $1 == "endif"  )   --l ;                               \
	else if ( e[l] ) print \
	} \
function defined(def, defs,i) \
	{ \
	split(tokens,defs) ; \
	for ( i in defs ) \
		if ( defs[i]==def ) \
			return 1 ; \
	return 0 ; \
	} ' \
	tokens="$*" $file