Use memcpy() instead of memmove() or Xtmemmove()

Merged Alan Coopersmith requested to merge alanc/libxt:misc into master

Most of these came from a mass bcopy() -> memmove() substitution in 1993 with a commit comment of "ANSI-fication".

I also dropped many unnecessary (char *) casts from the arguments, since memcpy is defined as taking void * parameters.

Merge request reports