c-decl.c (warn_if_shadowing): Don't warn if shadowed identifier is from system header.

	* c-decl.c (warn_if_shadowing): Don't warn if shadowed
	identifier is from system header.

From-SVN: r181684

gcc/ChangeLog

+2011-11-24  Alan Modra  <amodra@gmail.com>
+
+	* c-decl.c (warn_if_shadowing): Don't warn if shadowed
+	identifier is from system header.
+
 2011-11-23  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/51261
@@ -104,7 +109,7 @@
 
 	PR c++/51264
 	* tree.c (iterative_hash_expr): Remove break after return.
-	
+
 2011-11-22  Iain Sandoe  <iains@gcc.gnu.org>
 
 	* target.def (tm_clone_table_section): New hook.

gcc/c-decl.c

@@ -2534,7 +2534,10 @@ warn_if_shadowing (tree new_decl)
 
   /* Is anything being shadowed?  Invisible decls do not count.  */
   for (b = I_SYMBOL_BINDING (DECL_NAME (new_decl)); b; b = b->shadowed)
-    if (b->decl && b->decl != new_decl && !b->invisible)
+    if (b->decl && b->decl != new_decl && !b->invisible
+	&& (b->decl == error_mark_node
+	    || diagnostic_report_warnings_p (global_dc,
+					     DECL_SOURCE_LOCATION (b->decl))))
       {
 	tree old_decl = b->decl;