Import prebuilt clang toolchain for linux.
diff --git a/linux-x64/clang/include/llvm/ExecutionEngine/OrcMCJITReplacement.h b/linux-x64/clang/include/llvm/ExecutionEngine/OrcMCJITReplacement.h
new file mode 100644
index 0000000..4cd5648
--- /dev/null
+++ b/linux-x64/clang/include/llvm/ExecutionEngine/OrcMCJITReplacement.h
@@ -0,0 +1,38 @@
+//===---- OrcMCJITReplacement.h - Orc-based MCJIT replacement ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file forces OrcMCJITReplacement to link in on certain operating systems.
+// (Windows).
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_EXECUTIONENGINE_ORCMCJITREPLACEMENT_H
+#define LLVM_EXECUTIONENGINE_ORCMCJITREPLACEMENT_H
+
+#include "llvm/ExecutionEngine/ExecutionEngine.h"
+#include <cstdlib>
+
+extern "C" void LLVMLinkInOrcMCJITReplacement();
+
+namespace {
+  struct ForceOrcMCJITReplacementLinking {
+    ForceOrcMCJITReplacementLinking() {
+      // We must reference OrcMCJITReplacement in such a way that compilers will
+      // not delete it all as dead code, even with whole program optimization,
+      // yet is effectively a NO-OP. As the compiler isn't smart enough to know
+      // that getenv() never returns -1, this will do the job.
+      if (std::getenv("bar") != (char*) -1)
+        return;
+
+      LLVMLinkInOrcMCJITReplacement();
+    }
+  } ForceOrcMCJITReplacementLinking;
+}
+
+#endif