Import prebuilt clang toolchain for linux.
diff --git a/linux-x64/clang/include/llvm/Support/thread.h b/linux-x64/clang/include/llvm/Support/thread.h
new file mode 100644
index 0000000..787a513
--- /dev/null
+++ b/linux-x64/clang/include/llvm/Support/thread.h
@@ -0,0 +1,53 @@
+//===-- llvm/Support/thread.h - Wrapper for <thread> ------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This header is a wrapper for <thread> that works around problems with the
+// MSVC headers when exceptions are disabled. It also provides llvm::thread,
+// which is either a typedef of std::thread or a replacement that calls the
+// function synchronously depending on the value of LLVM_ENABLE_THREADS.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_THREAD_H
+#define LLVM_SUPPORT_THREAD_H
+
+#include "llvm/Config/llvm-config.h"
+
+#if LLVM_ENABLE_THREADS
+
+#include <thread>
+
+namespace llvm {
+typedef std::thread thread;
+}
+
+#else // !LLVM_ENABLE_THREADS
+
+#include <utility>
+
+namespace llvm {
+
+struct thread {
+  thread() {}
+  thread(thread &&other) {}
+  template <class Function, class... Args>
+  explicit thread(Function &&f, Args &&... args) {
+    f(std::forward<Args>(args)...);
+  }
+  thread(const thread &) = delete;
+
+  void join() {}
+  static unsigned hardware_concurrency() { return 1; };
+};
+
+}
+
+#endif // LLVM_ENABLE_THREADS
+
+#endif