The problem with clock_nanosleep() restarting was that the address of
the users return timespec was being saved at the wrong place.  In needs
to be saved in the sys call interface code rather than the
do_clock_nanosleep().  My original tests were a bit weak as they only
did one signal rather than two or more which were required to break it. 

The attached patch fixes the problem.

I also added a few comments about how restart works, and added my name
to the MAINTAINERS list.