Let libX11 load and make available the newer (X11R6) callback-based API
for XIM (expected by emacs).

Patch from Ian D. Leroux <idleroux@fastmail.fm> on pkgsrc-users
following a hint by Nhat Minh Lê <nhat.minh.le@gmail.com>.

fix a couple of defaults that make emacs and a few other things work.
as reported on tech-x11.

initial import of libX11-1.1.4