Add has_feature support for reflecting the presence of refined Objective-C ABI mangling for qualified id<...>.  Fixes <rdar://problem/14799110>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@192643 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp
index 2717846..9c998ea 100644
--- a/lib/Lex/PPMacroExpansion.cpp
+++ b/lib/Lex/PPMacroExpansion.cpp
@@ -897,6 +897,7 @@
            .Case("objc_modules", LangOpts.ObjC2 && LangOpts.Modules)
            .Case("objc_nonfragile_abi", LangOpts.ObjCRuntime.isNonFragile())
            .Case("objc_property_explicit_atomic", true) // Does clang support explicit "atomic" keyword?
+           .Case("objc_protocol_qualifier_mangling", true)
            .Case("objc_weak_class", LangOpts.ObjCRuntime.hasWeakClassImport())
            .Case("ownership_holds", true)
            .Case("ownership_returns", true)