Add several GCC attributes that should only be associated with functi…

…ons:

leaf, artificial, and warn_unused_result.  These are all heavily used in
<stdio.h> under Fedora 17 (glibc 2.15) when optimization is turned on.
Without this fix, these attributes tend to be incorrectly associated with
functions' return types, which in turn leads to GCC warnings about
incorrect attribute use.

src/cil.ml

@@ -1395,7 +1395,9 @@ let attributeHash: (string, attributeClass) H.t =
 
   List.iter (fun a -> H.add table a (AttrFunType false))
     [ "format"; "regparm"; "longcall"; 
-      "noinline"; "always_inline"; ];
+      "noinline"; "always_inline"; "leaf";
+      "artificial"; "warn_unused_result";
+    ];
 
   List.iter (fun a -> H.add table a (AttrFunType true))
     [ "stdcall";"cdecl"; "fastcall" ];