Don't provide a fallback definition #ifdef X_NOT_POSIX anymore.
We already use size_t throughout the rest of Xlib, just had this
one instance left in XKBGAlloc.c of a fallback definition.
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Backported-to-NX-by: Ulrich Sibiller <uli42@gmx.de>