buildenv/1.3.x/win32-static: fix 'syntax error' in setup.cmd when WANT_WIN64_BUILDENV is not set.
buildenv/1.3.x/win32-static: fix 'syntax error' in setup.cmd when WANT_WIN64_BUILDENV is not set.

ccpgames/mumble-releng,ccpgames/mumble-releng