Update clang to r339409.

Change-Id: I800772d2d838223be1f6b40d490c4591b937fca2
diff --git a/linux-x64/clang/include/llvm/Support/VCSRevision.h b/linux-x64/clang/include/llvm/Support/VCSRevision.h
index 8510ea2..914d51a 100644
--- a/linux-x64/clang/include/llvm/Support/VCSRevision.h
+++ b/linux-x64/clang/include/llvm/Support/VCSRevision.h
@@ -1 +1 @@
-#define LLVM_REVISION "git-1d739ffb036"
+#define LLVM_REVISION "git-c822c63a8c6"