accept -x objc-cpp-output as an alias for -x objective-c-cpp-output,
per PR9577


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@129201 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index df876d8..3d6d9d9 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -1189,6 +1189,7 @@
       .Case("assembler-with-cpp", IK_Asm)
       .Case("c++-cpp-output", IK_PreprocessedCXX)
       .Case("objective-c-cpp-output", IK_PreprocessedObjC)
+      .Case("objc-cpp-output", IK_PreprocessedObjC)
       .Case("objective-c++-cpp-output", IK_PreprocessedObjCXX)
       .Case("c-header", IK_C)
       .Case("objective-c-header", IK_ObjC)