Make CXLanguage_Invalid the first enum value (with '0' as its value) in CXLanguageKind.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101287 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang-c/Index.h b/include/clang-c/Index.h
index 8cc5382..1bf5a46 100644
--- a/include/clang-c/Index.h
+++ b/include/clang-c/Index.h
@@ -948,10 +948,10 @@
  * \brief Describe the "language" of the entity referred to by a cursor.
  */
 CINDEX_LINKAGE enum CXLanguageKind {
+  CXLanguage_Invalid = 0,
   CXLanguage_C,
   CXLanguage_ObjC,
-  CXLanguage_CPlusPlus,
-  CXLanguage_Invalid
+  CXLanguage_CPlusPlus
 };
 
 /**