#!/bin/sh

usage() {
cat <<EOF
Usage: $0 [OPTION]... [VAR=VALUE]...

To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE.

  CC      C compiler command [detected]
  CFLAGS  C compiler flags [-g, ...]

EOF
exit 0
}

echo () { printf "%s\n" "$*" ; }
cmdexists () { type "$1" >/dev/null 2>&1 ; }
trycc () { test -z "$CC" && cmdexists "$1" && CC=$1 ; }

prefix=/usr/bin/
CFLAGS="-Wall -Wextra -O2"
LDFLAGS=
CC=

for arg ; do
case "$arg" in
--help|h) usage ;;
CFLAGS=*) CFLAGS=${arg#*=} ;;
LDFLAGS=*) LDFLAGS=${arg#*=} ;;
esac
done

printf "checking for C compiler... "
trycc gcc
trycc cc
trycc clang
printf "%s\n" "$CC"

printf "checking for xxd... "
trycc xxd

printf "checking weather C compiler works... "
status="fail"
tmpc="$(mktemp -d)/test.c"
echo "typedef int x;" > "$tmpc"
if output=$($CC $CFLAGS -c -o /dev/null "$tmpc" 2>&1) ; then
printf "yes\n"
else
printf "no; %s\n" "$output"
exit 1
fi

printf "creating config.mak... "
printf "PREFIX=%s\n" "$prefix" > config.mak
printf "CFLAGS=%s\n" "$CFLAGS" >> config.mak
printf "LDFLAGS=%s\n" "$LDFLAGS" >> config.mak
printf "CC=%s\n" "$CC" >> config.mak
printf "done\n"