MC/Mach-O: Stub out explicit MCMachObjectTargetWriter interface.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121973 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMAsmBackend.cpp b/lib/Target/ARM/ARMAsmBackend.cpp
index bd871c0..9556a7d 100644
--- a/lib/Target/ARM/ARMAsmBackend.cpp
+++ b/lib/Target/ARM/ARMAsmBackend.cpp
@@ -28,6 +28,9 @@
 using namespace llvm;
 
 namespace {
+class ARMMachObjectWriter : public MCMachObjectTargetWriter {
+};
+
 class ARMAsmBackend : public TargetAsmBackend {
   bool isThumbMode;  // Currently emitting Thumb code.
 public:
@@ -382,7 +385,8 @@
 
   MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
     // FIXME: Subtarget info should be derived. Force v7 for now.
-    return createMachObjectWriter(OS, /*Is64Bit=*/false,
+    return createMachObjectWriter(new ARMMachObjectWriter,
+                                  OS, /*Is64Bit=*/false,
                                   object::mach::CTM_ARM,
                                   object::mach::CSARM_V7,
                                   /*IsLittleEndian=*/true);