disable c4267 for hunspell for building on win x64

TBR=jschuh@chromium.org
BUG=167187

Review URL: https://chromiumcodereview.appspot.com/11823057

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/hunspell@176100 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
1 file changed