Mangle extern "C" functions whose names are not simple identifiers.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175166 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGenCXX/c-linkage.cpp b/test/CodeGenCXX/c-linkage.cpp
index c31ad43..cec9e28 100644
--- a/test/CodeGenCXX/c-linkage.cpp
+++ b/test/CodeGenCXX/c-linkage.cpp
@@ -22,3 +22,10 @@
     test2_f();
   }
 }
+
+extern "C" {
+  struct test3_s {
+  };
+  bool operator==(const int& a, const test3_s& b)  {
+  }
+}