Fix representation of gcov_info_type

[Jan Hubicka <hubicka at ucw dot cz>]

Hi,
This is first bug noticed by the type consistency checks I added.

gcov_info_type is a structure that contains function pointer to itself.  While
building it we first build a structure w/o size and fields, then we build a
function type that produces a qualified variant of the structure (not sure why
that legwork is needed). Then we add fields via finish_builtin_struct.
It sets the fields to structure but not its variant and then does layout_type
that actually copies size to all variants. So we end up with TYPE_COMPLETE_P variant
that has size but no fields.  This is quite obviously wrong.

Fixed thus. Bootstrapped, lto-bootstrapped and regtested x86_64-linux, comitted.

	* stor-layout.c (finish_builtin_struct): Copy fields into
	the variants.

Index: stor-layout.c
===================================================================
--- stor-layout.c	(revision 212098)
+++ stor-layout.c	(working copy)
@@ -2065,7 +2065,7 @@ void
 finish_builtin_struct (tree type, const char *name, tree fields,
 		       tree align_type)
 {
-  tree tail, next;
+  tree tail, next, variant;
 
   for (tail = NULL_TREE; fields; tail = fields, fields = next)
     {
@@ -2074,6 +2074,10 @@ finish_builtin_struct (tree type, const
       DECL_CHAIN (fields) = tail;
     }
   TYPE_FIELDS (type) = tail;
+  for (variant = TYPE_MAIN_VARIANT (type);
+       variant != 0;
+       variant = TYPE_NEXT_VARIANT (variant))
+    TYPE_FIELDS (variant) = tail;
 
   if (align_type)
     {