configure.in: no visibility option for older GCC

* configure.in (visibility_option): visibility attribute is not
  available before GCC 4, so do not use -fvisibility option in that
  case.  [ruby-core:48147] [Bug #7205]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37296 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Tue Oct 23 14:06:47 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in (visibility_option): visibility attribute is not
+	  available before GCC 4, so do not use -fvisibility option in that
+	  case.  [ruby-core:48147] [Bug #7205]
+
 Tue Oct 23 12:57:29 2012  Koichi Sasada  <ko1@atdot.net>
 
 	* vm_core.h, vm_insnhelper.c, vm_eval.c (OPT_CALL_CFUNC_WITHOUT_FRAME):

configure.in

@@ -644,7 +644,15 @@ if test "$GCC" = ""; then
     AS_CASE(["$target_os"],[aix*],[warnflags="$warnflags -qinfo=por" rb_cv_warnflags="$rb_cv_warnflags -qinfo=por"])
 fi
 if test "$GCC" = yes; then
-    RUBY_TRY_CFLAGS(-fvisibility=hidden, [RUBY_APPEND_OPTION(XCFLAGS, -fvisibility=hidden)])
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([
+	@%:@if !(defined __GNUC__ && __GNUC__ >= 4)
+	@%:@error not GCC 4 or later
+	>>>not GCC 4 or later<<<
+	@%:@endif])],
+	[visibility_option=yes], [visibility_option=no])
+    if test "$visibility_option" = yes; then
+	RUBY_TRY_CFLAGS(-fvisibility=hidden, [visibility_option=yes], [visibility_option=no])
+    fi
     AC_SUBST(WERRORFLAG, "-Werror")
     if test "$visibility_option" = yes; then
 	RUBY_APPEND_OPTION(XCFLAGS, -fvisibility=hidden)