libvpx: Pull from upstream

source/libvpx/vp8/common/generic/systemdependent.c

Index: source/libvpx/vp8/common/generic/systemdependent.c
diff --git a/source/libvpx/vp8/common/generic/systemdependent.c b/source/libvpx/vp8/common/generic/systemdependent.c
index 4393ced48c80a3bb1648ede08916817908ff4d2d..28dc262ae5a2c1c935a213c3f2977de80b679892 100644
--- a/source/libvpx/vp8/common/generic/systemdependent.c
+++ b/source/libvpx/vp8/common/generic/systemdependent.c
@@ -45,6 +45,10 @@ static int get_cpu_count()
 #endif
 #elif defined(_WIN32)
     {
+#if _WIN32_WINNT >= 0x0501
+        SYSTEM_INFO sysinfo;
+        GetNativeSystemInfo(&sysinfo);
+#else
         PGNSI pGNSI;
         SYSTEM_INFO sysinfo;
 
@@ -57,6 +61,7 @@ static int get_cpu_count()
             pGNSI(&sysinfo);
         else
             GetSystemInfo(&sysinfo);
+#endif
 
         core_count = sysinfo.dwNumberOfProcessors;
     }