In C++, allow builtins to be referred to via qualified name lookup, e.g.,

  ::__builtin_va_copy

Fixes one of the Firefox issues in PR5511.

llvm-svn: 95966
diff --git a/clang/test/SemaCXX/builtins.cpp b/clang/test/SemaCXX/builtins.cpp
index a75b4f2e..568ba5d 100644
--- a/clang/test/SemaCXX/builtins.cpp
+++ b/clang/test/SemaCXX/builtins.cpp
@@ -5,3 +5,5 @@
 void f() {
   (void)CFStringRef(CFSTR("Hello"));
 }
+
+void a() { __builtin_va_list x, y; ::__builtin_va_copy(x, y); }