[Libreoffice] MinGW cross-compilation: Runs!

Hi all,

Based on Tor's, Fridrich's, and others great work, I was able to get the
MinGW cross-compilation to state that it not only builds, but even
runs! :-)  The good thing about all this is that with this, you do not
need a Windows machine at all to be able to produce LibreOffice Windows
executable.  Even debugging can be done on Linux, using wine.

The full description is here:

  http://cgit.freedesktop.org/libreoffice/core/tree/README.cross#n63

Few highlights:

- use the pre-build MinGW packages from OBS
  [http://en.opensuse.org/Portal:Build_Service], it will save you lots
  of pain
- don't expect a nice installer, the result of build is just a tarball
  containing the executable and libraries
- the resulting build works under wine
- you can use winedbg to debug that

You might have noticed that there is a tinderbox that builds the MinGW
builds regularly, and I am fixing the breakages when they are not fixed
by the committer for a long time ;-), so the code should not bitrot that
easily.  I have also enabled uploading of the build results to
http://dev-builds.libreoffice.org , the first ones should appear there
shortly.  Most probably they won't run out of the box, because they will
be missing the .dlls that come from the OBS MinGW project - but I'll
adapt scp2 to include them.

All in all - enjoy! :-)  Would be great to see more people hacking on
this; it is an exciting new world, and lots of things can (and should)
be improved - see the TODO in the README.cross.

Regards,
Kendy