[Libreoffice] Windows (MSVC) incremental build is broken.

[Tor Lillqvist]

> Kendy (this time CC'd), please don't commit this stuff.  It breaks
> incremental build on Windows, making debugging Windows impossible.

Hear, hear. If we want beta1 to be better than beta0, we can't require
people having to make clean after each edit, and rebuild from scratch
(effectively making the fix-test-commit cycle take one day).

--tml