Import prebuilt clang toolchain for linux.
diff --git a/linux-x64/clang/include/lld/Core/Writer.h b/linux-x64/clang/include/lld/Core/Writer.h
new file mode 100644
index 0000000..1f0ca4c
--- /dev/null
+++ b/linux-x64/clang/include/lld/Core/Writer.h
@@ -0,0 +1,47 @@
+//===- lld/Core/Writer.h - Abstract File Format Interface -----------------===//
+//
+// The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_CORE_WRITER_H
+#define LLD_CORE_WRITER_H
+
+#include "lld/Common/LLVM.h"
+#include "llvm/Support/Error.h"
+#include <memory>
+#include <vector>
+
+namespace lld {
+class File;
+class LinkingContext;
+class MachOLinkingContext;
+
+/// \brief The Writer is an abstract class for writing object files, shared
+/// library files, and executable files. Each file format (e.g. mach-o, etc)
+/// has a concrete subclass of Writer.
+class Writer {
+public:
+ virtual ~Writer();
+
+ /// \brief Write a file from the supplied File object
+ virtual llvm::Error writeFile(const File &linkedFile, StringRef path) = 0;
+
+ /// \brief This method is called by Core Linking to give the Writer a chance
+ /// to add file format specific "files" to set of files to be linked. This is
+ /// how file format specific atoms can be added to the link.
+ virtual void createImplicitFiles(std::vector<std::unique_ptr<File>> &) {}
+
+protected:
+ // only concrete subclasses can be instantiated
+ Writer();
+};
+
+std::unique_ptr<Writer> createWriterMachO(const MachOLinkingContext &);
+std::unique_ptr<Writer> createWriterYAML(const LinkingContext &);
+} // end namespace lld
+
+#endif
