1set -e
 2
 3if [ "$#" -lt 3 ] ; then
 4	printf 'usage: %s var out command...\n' "$0" >&2
 5	exit 2
 6fi
 7
 8var=$1
 9out=$2
10shift 2
11for size in 8 4 2 1 ; do
12	echo "==> trying $var=$size..." >&2
13	if "$@" -D "$var=$size" ; then
14		echo '==> success' >&2
15		echo "#define $var $size" >"$out"
16		exit 0
17	fi
18done 2>"$out.log"
19
20cat "$out.log"
21printf "%s: could not determine %s\n" "$0" "$var" >&2
22exit 1