Add new checker-specific attribute 'objc_ownership_returns'. This isn't hooked

up to the checker yet, but essentially it allows a user to specify that an
Objective-C method or C function returns an owned an Objective-C object.

llvm-svn: 70001

clang/lib/Frontend/PCHWriter.cpp

@@ -2181,6 +2181,7 @@ void PCHWriter::WriteAttributeRecord(const Attr *Attr) {
 
     case Attr::ObjCException:
     case Attr::ObjCNSObject:
+    case Attr::ObjCOwnershipReturns:
     case Attr::Overloadable:
       break;