Import prebuilt clang toolchain for linux.
diff --git a/linux-x64/clang/include/llvm/CodeGen/GCs.h b/linux-x64/clang/include/llvm/CodeGen/GCs.h
new file mode 100644
index 0000000..5207f80
--- /dev/null
+++ b/linux-x64/clang/include/llvm/CodeGen/GCs.h
@@ -0,0 +1,46 @@
+//===-- GCs.h - Garbage collector linkage hacks ---------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains hack functions to force linking in the GC components.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_GCS_H
+#define LLVM_CODEGEN_GCS_H
+
+namespace llvm {
+class GCStrategy;
+class GCMetadataPrinter;
+
+/// FIXME: Collector instances are not useful on their own. These no longer
+/// serve any purpose except to link in the plugins.
+
+/// Creates a CoreCLR-compatible garbage collector.
+void linkCoreCLRGC();
+
+/// Creates an ocaml-compatible garbage collector.
+void linkOcamlGC();
+
+/// Creates an ocaml-compatible metadata printer.
+void linkOcamlGCPrinter();
+
+/// Creates an erlang-compatible garbage collector.
+void linkErlangGC();
+
+/// Creates an erlang-compatible metadata printer.
+void linkErlangGCPrinter();
+
+/// Creates a shadow stack garbage collector. This collector requires no code
+/// generator support.
+void linkShadowStackGC();
+
+void linkStatepointExampleGC();
+}
+
+#endif