Remove use_sysroot=0

source/scale_win.cc

 /*
  *  Copyright 2013 The LibYuv Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS. All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 271 matching lines @@
     vmovdqu     ymm1, [eax + 32]
     vmovdqu     ymm2, [eax + esi]
     vmovdqu     ymm3, [eax + esi + 32]
     lea         eax,  [eax + 64]
     vpmaddubsw  ymm0, ymm0, ymm4      // horizontal add
     vpmaddubsw  ymm1, ymm1, ymm4
     vpmaddubsw  ymm2, ymm2, ymm4
     vpmaddubsw  ymm3, ymm3, ymm4
     vpaddw      ymm0, ymm0, ymm2      // vertical add
     vpaddw      ymm1, ymm1, ymm3
-    vpsrlw      ymm0, ymm0, 1
+    vpsrlw      ymm0, ymm0, 1         // (x + 2) / 4 = (x / 2 + 1) / 2
     vpsrlw      ymm1, ymm1, 1
     vpavgw      ymm0, ymm0, ymm5      // (x + 1) / 2
     vpavgw      ymm1, ymm1, ymm5
     vpackuswb   ymm0, ymm0, ymm1
     vpermq      ymm0, ymm0, 0xd8      // unmutate vpackuswb
     vmovdqu     [edx], ymm0
     lea         edx, [edx + 32]
     sub         ecx, 32
     jg          wloop
 
@@ skipping 1045 matching lines @@
     idiv       ecx
     ret
   }
 }
 #endif  // !defined(LIBYUV_DISABLE_X86) && defined(_M_IX86)
 
 #ifdef __cplusplus
 }  // extern "C"
 }  // namespace libyuv
 #endif