[Libreoffice] instructions for building on windows with OneGit

[Tor Lillqvist]

> strUserID: S-1-5-21-3395787511-4075999146-953599952
> comes from qa/osl/security/osl_Security.cxx
> 
> strID: S-1-5-21-3395787511-4075999146-953599952-1000
> comes from osl/w32/security.c

Hmm, for me, if I add code to just print out the aMessage even if the assertion doesn't fail, I see:

strUserID: S-1-5-21-2895500082-1622916122-3903545024-1000, strID: S-1-5-21-2895500082-1622916122-3903545024-1000

weird...

--tml