Add a gyp variable build_dir_prefix to control the output
directory of the build on Windows.

BUG=97678


Review URL: http://codereview.chromium.org/8046024

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@103054 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed