dnl Autoconf extension macros for libIDL
AC_DEFUN(AC_CPP_ACCEPT_IDL,
	[AC_CACHE_CHECK([if C preprocessor likes IDL],
		ac_cv_cpp_accept_idl,
		[AC_TRY_CPP([
			#pragma prefix "foo.org"
			module FOO {
				typedef unsigned long long big;
				interface BAR {
					readonly attribute big number;
				};
			};
		],
		ac_cv_cpp_accept_idl=yes,
		ac_cv_cpp_accept_idl=no)])])

AC_DEFUN(AC_CPP_PIPE_STDIN,
	[AC_CACHE_CHECK([if C preprocessor can read from stdin],
		ac_cv_cpp_pipe_stdin,
		[AC_REQUIRE_CPP
		if echo | $CPP - 2>/dev/null 1>&2 ; then
			ac_cv_cpp_pipe_stdin=yes
		else
			ac_cv_cpp_pipe_stdin=no
		fi])
	if test $ac_cv_cpp_pipe_stdin = yes ; then
		AC_DEFINE(HAVE_CPP_PIPE_STDIN)
	fi])

AC_DEFUN(AC_UPDATE_IF_CHANGED,
	[if test -f "$2"; then
		if cmp -s "$1" "$2" 2>/dev/null; then
			echo "$1 is unchanged"
		else
			echo "$1 has changed"
			rm -f "$1"
			cp "$2" "$1"
		fi
	fi])

AC_DEFUN(AC_CPP_NOSTDINC,
       [AC_CACHE_CHECK([how to ignore standard include path],
               ac_cv_cpp_nostdinc,
               [saved_CPPFLAGS="$CPPFLAGS"
               CPPFLAGS="$CPPFLAGS -I-"
               AC_TRY_CPP(,ac_cv_cpp_nostdinc=-I-,
                       [CPPFLAGS="$saved_CPPFLAGS -I"
                       AC_TRY_CPP(,ac_cv_cpp_nostdinc=-I,)])
               CPPFLAGS="$saved_CPPFLAGS"])
       AC_DEFINE_UNQUOTED(CPP_NOSTDINC, "$ac_cv_cpp_nostdinc")])