Update clang to r339409b.

Change-Id: Ied8a188bb072c40035320acedc86164b66d920af
diff --git a/linux-x64/clang/include/llvm/Config/llvm-config.h b/linux-x64/clang/include/llvm/Config/llvm-config.h
index 5e0844c..5895e85 100644
--- a/linux-x64/clang/include/llvm/Config/llvm-config.h
+++ b/linux-x64/clang/include/llvm/Config/llvm-config.h
@@ -72,10 +72,10 @@
 #define LLVM_VERSION_MINOR 0
 
 /* Patch version of the LLVM API */
-#define LLVM_VERSION_PATCH 1
+#define LLVM_VERSION_PATCH 4
 
 /* LLVM version string */
-#define LLVM_VERSION_STRING "8.0.1svn"
+#define LLVM_VERSION_STRING "8.0.4svn"
 
 /* Whether LLVM records statistics for use with GetStatistics(),
  * PrintStatistics() or PrintStatisticsJSON()