buildenv/1.3.x/win32-static: use pristine .vcxproj file for x64 builds of FLAC now that they're supported by upstream.
buildenv/1.3.x/win32-static: use pristine .vcxproj file for x64 builds of FLAC now that they're supported by upstream.

ccpgames/mumble-releng,ccpgames/mumble-releng