libvpx: Pull from upstream

source/libvpx/vp9/common/vp9_systemdependent.h

Index: source/libvpx/vp9/common/vp9_systemdependent.h
===================================================================
--- source/libvpx/vp9/common/vp9_systemdependent.h	(revision 251189)
+++ source/libvpx/vp9/common/vp9_systemdependent.h	(working copy)
@@ -11,15 +11,19 @@
 #ifndef VP9_COMMON_VP9_SYSTEMDEPENDENT_H_
 #define VP9_COMMON_VP9_SYSTEMDEPENDENT_H_
 
+#ifdef _MSC_VER
+# if _MSC_VER > 1310 && (defined(_M_X64) || defined(_M_IX86))
+#  include <intrin.h>
+#  define USE_MSC_INTRIN
+# endif
+# include <math.h>
+# define snprintf _snprintf
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-#ifdef _MSC_VER
-#include <math.h>
-#define snprintf _snprintf
-#endif
-
 #include "./vpx_config.h"
 #if ARCH_X86 || ARCH_X86_64
 void vpx_reset_mmx_state(void);
@@ -30,7 +34,7 @@
 
 #if defined(_MSC_VER) && _MSC_VER < 1800
 // round is not defined in MSVC before VS2013.
-static int round(double x) {
+static INLINE int round(double x) {
   if (x < 0)
     return (int)ceil(x - 0.5);
   else
@@ -44,9 +48,7 @@
 static INLINE int get_msb(unsigned int n) {
   return 31 ^ __builtin_clz(n);
 }
-#elif defined(_MSC_VER) && _MSC_VER > 1310 && \
-      (defined(_M_X64) || defined(_M_IX86))
-#include <intrin.h>
+#elif defined(USE_MSC_INTRIN)
 #pragma intrinsic(_BitScanReverse)
 
 static INLINE int get_msb(unsigned int n) {
@@ -54,6 +56,7 @@
   _BitScanReverse(&first_set_bit, n);
   return first_set_bit;
 }
+#undef USE_MSC_INTRIN
 #else
 // Returns (int)floor(log2(n)). n must be > 0.
 static INLINE int get_msb(unsigned int n) {