Only use the visibility attribute in gcc 4.0 or newer

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%401602

include/begin_code.h

@@ -60,7 +60,7 @@
 #   define DECLSPEC
 #  endif
 # else
-#  if defined(__GNUC__)
+#  if defined(__GNUC__) && __GNUC__ >= 4
 #   define DECLSPEC	__attribute__ ((visibility("default")))
 #  else
 #   define DECLSPEC