branches: 1.1.1.1.2; 1.1.1.1.4; 1.1.1.1.6; 1.1.1.1.28;
initial import of the crossbuild framework for modular Xorg. this
is heavily based upon the work rtr@ did on src/x11, but hacked to
work for modern modular Xorg source split.

the sources will live in xsrc/external/mit/<package>/dist.

documentation on using this will come when the above directories
are fully populated. there are 192 of them so it may take some time
before that is completed.