Implement declaration merging for Objective-C protocols across
multiple, disjoint modules. There is far too much duplicating with the
ObjCInterfaceDecl case here, which I'll eliminate shortly.

llvm-svn: 147417
diff --git a/clang/test/Modules/Inputs/redecl-merge-right.h b/clang/test/Modules/Inputs/redecl-merge-right.h
index c5e35b1..82051d4 100644
--- a/clang/test/Modules/Inputs/redecl-merge-right.h
+++ b/clang/test/Modules/Inputs/redecl-merge-right.h
@@ -42,6 +42,11 @@
 
 struct explicit_struct;
 
+@protocol P4, P3;
+@protocol P3;
+@protocol P3;
+@protocol P3;
+
 #ifdef __cplusplus
 template<typename T> class Vector { 
 public: