tree.c (walk_tree): Don't recurse into DECL_INITIAL or DECL_SIZE unless...

	* tree.c (walk_tree): Don't recurse into DECL_INITIAL or DECL_SIZE
	unless we're declaring the variable in question.

From-SVN: r30815

gcc/testsuite/g++.old-deja/g++.other/decl7.C

+// Build don't link:
+// Origin: Mark Mitchell <mark@codesourcery.com>
+
+struct S 
+{
+  void* sp;
+};
+
+void* f ()
+{
+  struct S s = { &s.sp };
+  return s.sp;
+}