This makes the region code changes source compatible with existing
code, although none of them are used within the server source itself.

In NX, this patch is not really necessary, but it has been backported
with the previous patches for the sake of backporting the complete
mi/miregion.c -> dix/region.c change in X.Org.

v1: Keith Packard <keithp@keithp.com>
v2: Mike Gabriel <mike.gabriel@das-netzwerkteam.de> (backported to nx-libs)