Update clang to r339409.

Change-Id: I800772d2d838223be1f6b40d490c4591b937fca2
diff --git a/linux-x64/clang/include/llvm/Support/AlignOf.h b/linux-x64/clang/include/llvm/Support/AlignOf.h
index abd19af..9e7a62b 100644
--- a/linux-x64/clang/include/llvm/Support/AlignOf.h
+++ b/linux-x64/clang/include/llvm/Support/AlignOf.h
@@ -20,7 +20,7 @@
 namespace llvm {
 
 /// \struct AlignedCharArray
-/// \brief Helper for building an aligned character array type.
+/// Helper for building an aligned character array type.
 ///
 /// This template is used to explicitly build up a collection of aligned
 /// character array types. We have to build these up using a macro and explicit
@@ -34,12 +34,12 @@
 
 template<std::size_t Alignment, std::size_t Size>
 struct AlignedCharArray {
-  LLVM_ALIGNAS(Alignment) char buffer[Size];
+  alignas(Alignment) char buffer[Size];
 };
 
 #else // _MSC_VER
 
-/// \brief Create a type with an aligned char buffer.
+/// Create a type with an aligned char buffer.
 template<std::size_t Alignment, std::size_t Size>
 struct AlignedCharArray;
 
@@ -124,7 +124,7 @@
 };
 } // end namespace detail
 
-/// \brief This union template exposes a suitably aligned and sized character
+/// This union template exposes a suitably aligned and sized character
 /// array member which can hold elements of any of up to ten types.
 ///
 /// These types may be arrays, structs, or any other types. The goal is to