# GCC 4.x -fvisibility=hidden

AC_DEFUN([CHECK_GCC_FVISIBILITY], [
	AC_LANG_PUSH([C])
	saved_CFLAGS="$CFLAGS"
	CFLAGS="$saved_CFLAGS -fvisibility=hidden"
	AC_CACHE_CHECK([whether compiler accepts -fvisibility=hidden],
	  [ac_cv_fvisibility_hidden], AC_COMPILE_IFELSE(
		[AC_LANG_SOURCE()],
		[ac_cv_fvisibility_hidden=yes],
		[ac_cv_fvisibility_hidden=no]
	))
	if test "$ac_cv_fvisibility_hidden" = "yes"; then
		AC_DEFINE([HAVE_VISIBILITY_HIDDEN], [1],
			[True if compiler supports -fvisibility=hidden])
		AC_SUBST([GCC_FVISIBILITY_HIDDEN], [-fvisibility=hidden])
	fi
	CFLAGS="$saved_CFLAGS"
	AC_LANG_POP([C])
])