configure

#!/bin/sh

CONFIG_DEBUG=1

while getopts hrd opt
do
	case $opt in
	h) cat <<EOF
\`configure' configures this package to adapt to many kinds of systems.

Usage: ./configure [-h] [-r|-d] [VAR=VALUE]...

To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE.  See below for descriptions of some of the useful variables.

Defaults for the options are specified in brackets.

Configuration:
  -h                      display this help and exit

Optional Features:
  -d                      configure a debug build (default)
  -r                      configure a release build

Some influential environment variables:
  CC              C compiler command [clang gcc cc]
  CFLAGS          C compiler flags [-O3 -Wall -fPIC] when -r specified, [-g -Wall -fPIC] else
  LDFLAGS         linker flags []

  BUILDDIR        where the binaries and documentations will be built [./build]

Use these variables to override the choices made by \`configure' or to help
it to find libraries and programs with nonstandard names/locations.

Report bugs to the package provider.
EOF
		exit 2 ;;
	r) unset CONFIG_DEBUG ;;
	d) CONFIG_DEBUG=1 ;;
	?) echo "Unknown option: $opt" ;;
	esac
done

shift $((OPTIND - 1))
[ ! -z "$*" ] && export -- "$@"

# Compilation
if [ -z "$CC" ]
then
	for CC in clang gcc cc
	do [ ! -z `which "$CC"` ] && break
	done
fi

if [ ! -z "$CC" ]
then echo "Using C compiler '$CC'"
else echo "Unable to find C compiler" ; exit 1
fi

if [ -z "$CFLAGS" ]
then
	if [ ! -z "$CONFIG_DEBUG" ]
	then CFLAGS='-g -Wall -fPIC'
	else CFLAGS='-O3 -Wall -fPIC'
	fi
fi
echo "Using C flags '$CFLAGS'"

echo "Using Linker flags: '$LDFLAGS'"

[ -z "$BUILDDIR" ] && BUILDDIR='./build'

cat - Makefile.part <<EOF > Makefile
CC=$CC
CFLAGS=$CFLAGS
LDFLAGS=$LDFLAGS

BUILDDIR=$BUILDDIR
EOF