ninja/mac: Add a temporary gnarly hack to let ninja parse chromium's build files.
ninja/mac: Add a temporary gnarly hack to let ninja parse chromium's build files.

With this, base builds (it doesn't use any 'copies' that use env vars in its name).
Once real envvar support is added, this will go away again. Until then, this makes
it possible to work on targets that don't need 'copies' with envvars.

BUG=96894
TBR=tony
Review URL: http://codereview.chromium.org/9055002
old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google