libvpx: Pull from upstream

source/libvpx/vpx_ports/system_state.h

Index: source/libvpx/vpx_ports/system_state.h
diff --git a/source/libvpx/vpx_ports/msvc.h b/source/libvpx/vpx_ports/system_state.h
similarity index 59%
copy from source/libvpx/vpx_ports/msvc.h
copy to source/libvpx/vpx_ports/system_state.h
index 43a36e761841c367cb6d84ec8fc49b5851f646f5..086c64681f58ea44f535f12313aebb9c7e46546d 100644
--- a/source/libvpx/vpx_ports/msvc.h
+++ b/source/libvpx/vpx_ports/system_state.h
@@ -8,15 +8,15 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#ifndef VPX_PORTS_MSVC_H_
-#define VPX_PORTS_MSVC_H_
-#ifdef _MSC_VER
+#ifndef VPX_PORTS_SYSTEM_STATE_H_
+#define VPX_PORTS_SYSTEM_STATE_H_
 
 #include "./vpx_config.h"
 
-# if _MSC_VER < 1900  // VS2015 provides snprintf
-#  define snprintf _snprintf
-# endif  // _MSC_VER < 1900
-
-#endif  // _MSC_VER
-#endif  // VPX_PORTS_MSVC_H_
+#if ARCH_X86 || ARCH_X86_64
+void vpx_reset_mmx_state(void);
+#define vpx_clear_system_state() vpx_reset_mmx_state()
+#else
+#define vpx_clear_system_state()
+#endif  // ARCH_X86 || ARCH_X86_64
+#endif  // VPX_PORTS_SYSTEM_STATE_H_