[fpc-devel] unix calls moved to baseunix. Darwin untested.

[Marco van de Voort]

I committed the first in a series of patches that moves some elementary calls
from unit Unix to BaseUnix, as Michael and I agreed upon.

(lstat, get/set priority/nice map/unmap) for now.

I couldn't test darwin, but I'm reachable the entire day to fix problems
quickly which is why I did it today. (contact me on IRC or via mail, or simply
here)