AC_DEFUN([AC_RUBY_EXT], [
	AC_CHECK_PROG(RUBY, ruby)

	AC_ARG_WITH(ruby,
		[  --with-ruby=PATH        Location of Ruby executable (default: autodetect)],
		[rubybin="$withval"])

	AC_CHECK_PROGS(rubybin, ruby)

	rubyver=`$rubybin --version 2> /dev/null`
	if test -z "$rubyver"; then
		AC_MSG_ERROR([ruby binary not found!])
	fi

	AC_MSG_CHECKING(for Ruby library path)

	RUBYDIR=`($rubybin -rmkmf -e 'print Config::CONFIG[["archdir"]]') 2> /dev/null`
	if test -d "$RUBYDIR"; then
		AC_MSG_RESULT([$RUBYDIR])
	else
		AC_MSG_RESULT(not found)
		AC_MSG_ERROR(Ruby library path not found)
	fi

	AC_MSG_CHECKING(for Ruby site library path)
	RUBYSITEDIR=`($rubybin -rmkmf -e 'print Config::CONFIG[["sitearchdir"]]') 2> /dev/null`
	if test -d "$RUBYSITEDIR"; then
		AC_MSG_RESULT([$RUBYSITEDIR])
	else
		AC_MSG_RESULT(not found)
		AC_MSG_ERROR(Ruby site library path not found)
	fi

	AC_SUBST(RUBYDIR)
	AC_SUBST(RUBYSITEDIR)
])