Today, we landed code to use pymake by default on Windows on
mozilla-central and all derived project branches. Because of this, you
will need to clobber your windows builders .
If there are extenuating circumstances, you can ask releng to disable
pymake on your project branch. Please file a bug against us
(mozilla.org:Release Engineering) if you need this.
However, pymake is the new standard for Windows builds. At some point
you will *need* to make your project branch work with pymake, certainly
before merging back.