Integrate manifest merging library into LLD.

Summary: Now that the llvm-mt manifest merging libraries are complete, we may use them to merge manifests instead of needing to shell out to mt.exe.

Subscribers: mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D36255

llvm-svn: 311424

lib/WindowsManifest/WindowsManifestMerger.cpp

@@ -671,7 +671,7 @@ WindowsManifestMerger::WindowsManifestMergerImpl::~WindowsManifestMergerImpl() {
 
 Error WindowsManifestMerger::WindowsManifestMergerImpl::merge(
     const MemoryBuffer &Manifest) {
-  return Error::success();
+  return make_error<WindowsManifestError>("no libxml2");
 }
 
 std::unique_ptr<MemoryBuffer>