[fpc-pascal] FSplit is deprecated

[Marco van de Voort]

In our previous episode, Bernd said:
> > So use functions from 2.0.x like sysutils.extract*
> 
> Found it, thank you.
> 
> I was a little bit impatient yesterday, I should have searched a
> little longer on my own.
> 
> Due to the extraordinarily high quality of FPC  and Lazarus I have
> begun to take absolute perfection for granted and when I then
> accidentally stumble over one little trivial imperfection (every 6
> months or so) while I am in a hurry (always) it irritates me sometimes
> ;-)

Free Pascal has history. Nowadays the dos <-> sysutils split is not as bad
anymore, except for Turbo Vision code. But having two sets of everything is
not ideal.

Unixutil is a bit doubtful unit. It should be cleaned out, but some
functions can't move to their logical place (e.g. sysutils) because they are
used in units much lower in the hierarchy. (in units that are used to
implement units that are used to implement sysutils). So fully eliminating
it is hard.

Anyway, I started making notes about any deprecated functionality that has
been deprecated long, and will try to clean some of it out with 2.8.0. I
already started with cleansing the unix unit a bit in 2.7.1 (which has
routines deprecated since april 2007)