Blender Git Commit Log

Windows: Add sccache support.

sccache [1] is one of the few ccache like solutions that will
work on windows.

sccache support can be enabled with the `WITH_WINDOWS_SCCACHE`
cmake option however it will only will work with ninja as the
build system, msbuild is not supported currently.

Advanced option, developes are expected to obtain and configure
sccache on their own.

```
Full build no cache 1428.90s (100.00%)
Full build cached 434.34s ( 30.40%)
```

[1] https://github.com/mozilla/sccache

Reviewed By: nicholas_rishel, Brecht

Differential Revision: https://developer.blender.org/D7466