Fix C versus C++ linkage issue.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155842 91177308-0d34-0410-b5e6-96231b3b80d8

tools/libclang/CXCursor.cpp

@@ -1152,6 +1152,7 @@ CXCompletionString clang_getCursorCompletionString(CXCursor cursor) {
   }
   return NULL;
 }
+} // end: extern C.
 
 namespace {
   struct OverridenCursorsPool {
@@ -1176,6 +1177,7 @@ void cxcursor::disposeOverridenCXCursorsPool(void *pool) {
   delete static_cast<OverridenCursorsPool*>(pool);
 }
  
+extern "C" {
 void clang_getOverriddenCursors(CXCursor cursor,
                                 CXCursor **overridden,
                                 unsigned *num_overridden) {