Import prebuilt clang toolchain for linux.
diff --git a/linux-x64/clang/include/llvm/Support/ReverseIteration.h b/linux-x64/clang/include/llvm/Support/ReverseIteration.h
new file mode 100644
index 0000000..5e0238d
--- /dev/null
+++ b/linux-x64/clang/include/llvm/Support/ReverseIteration.h
@@ -0,0 +1,19 @@
+#ifndef LLVM_SUPPORT_REVERSEITERATION_H
+#define LLVM_SUPPORT_REVERSEITERATION_H
+
+#include "llvm/Config/abi-breaking.h"
+#include "llvm/Support/PointerLikeTypeTraits.h"
+
+namespace llvm {
+
+template<class T = void *>
+bool shouldReverseIterate() {
+#if LLVM_ENABLE_REVERSE_ITERATION
+ return detail::IsPointerLike<T>::value;
+#else
+ return false;
+#endif
+}
+
+}
+#endif