message: build: update AVX2 check
  _mm256_bslli_epi128() works in GCC 4.9.3+ only
  Android NDK r10 doesn't support this instruction
diff: @@ -6,5 +6,6 @@ void test()
  {
  int data[8] = {0,0,0,0, 0,0,0,0};
  __m256i a = _mm256_loadu_si256((const __m256i *)data);
  + __m256i b = _mm256_bslli_epi128(a, 1); // available in GCC 4.9.3+
  }
  int main() { return 0; }
  