Use raw_pwrite_stream in the object writer/streamer.

The ELF object writer will take advantage of that in the next commit.

llvm-svn: 234950
diff --git a/llvm/lib/Target/CppBackend/CPPBackend.cpp b/llvm/lib/Target/CppBackend/CPPBackend.cpp
index 8a9437b..0cb0bea 100644
--- a/llvm/lib/Target/CppBackend/CPPBackend.cpp
+++ b/llvm/lib/Target/CppBackend/CPPBackend.cpp
@@ -2149,11 +2149,9 @@
 //                       External Interface declaration
 //===----------------------------------------------------------------------===//
 
-bool CPPTargetMachine::addPassesToEmitFile(PassManagerBase &PM, raw_ostream &o,
-                                           CodeGenFileType FileType,
-                                           bool DisableVerify,
-                                           AnalysisID StartAfter,
-                                           AnalysisID StopAfter) {
+bool CPPTargetMachine::addPassesToEmitFile(
+    PassManagerBase &PM, raw_pwrite_stream &o, CodeGenFileType FileType,
+    bool DisableVerify, AnalysisID StartAfter, AnalysisID StopAfter) {
   if (FileType != TargetMachine::CGFT_AssemblyFile)
     return true;
   auto FOut = llvm::make_unique<formatted_raw_ostream>(o);