Make yasm compile on Win64

BUG=166496
TBR=scottmg

Review URL: https://chromiumcodereview.appspot.com/11698003

Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 52b471df00b5dc8191393ec191b2238e1e6c3ffa
1 file changed
tree: 9d2e47e8a1ff7fc99f02a07d6575b71ea1efceb3
  1. README.chromium
  2. source/
  3. yasm.gyp
  4. yasm_compile.gypi