Fix Visual Studio 2017 compilation.

When building with VC++ 2017 RC and its default header files the
intrin.h header file is less aggressively included by Windows headers.
This causes build breaks on Chrome x64 builds with VC++ 2017 RC when
X86MCTargetDesc.cpp uses __cpuid without first including its header.

https://github.com/google/swiftshader/pull/2

Change-Id: I664d7b509e0517b7621d41312ccdd0d3de60de84
Reviewed-on: https://swiftshader-review.googlesource.com/8951
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Nicolas Capens <capn@google.com>
diff --git a/third_party/LLVM/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp b/third_party/LLVM/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp
index f98d5e3..4156074 100644
--- a/third_party/LLVM/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp
+++ b/third_party/LLVM/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp
@@ -35,6 +35,10 @@
 #define GET_SUBTARGETINFO_MC_DESC
 #include "X86GenSubtargetInfo.inc"
 
+#ifdef _MSC_VER
+#include <intrin.h>
+#endif
+
 using namespace llvm;