Fix aom compile errors with VS2015

Import BUG=aomedia:900

third_party/aom/aom_ports/msvc.h

@@ -43,5 +43,25 @@ static INLINE long lroundf(float x) {
 }
 #endif  // _MSC_VER < 1800
 
+#if HAVE_AVX
+#include <immintrin.h>
+// Note:
+// _mm256_insert_epi16 intrinsics is available from vs2017.
+// We define this macro for vs2015 and earlier. The
+// intrinsics used here are in vs2015 document:
+// https://msdn.microsoft.com/en-us/library/hh977022.aspx
+// Input parameters:
+// a: __m256i,
+// d: int16_t,
+// indx: imm8 (0 - 15)
+#if _MSC_VER <= 1900
+#define _mm256_insert_epi16(a, d, indx)                                      \
+  _mm256_insertf128_si256(                                                   \
+      a,                                                                     \
+      _mm_insert_epi16(_mm256_extractf128_si256(a, indx >> 3), d, indx % 8), \
+      indx >> 3)
+#endif  // _MSC_VER <= 1900
+#endif  // HAVE_AVX
+
 #endif  // _MSC_VER
 #endif  // AOM_PORTS_MSVC_H_