Log Message:
Fix wrong hard-wired paths in patch-ab. (was using /usr/X11R6)
While here:
  - sprinkle stdlib.h widely to avoid undefined behavior calling malloc
  - fix randomizer setup (was calling srand() and then using random())
  - avoid installing a csh script, since we were replacing the entire
    contents of the file anyhow
  - add missing libXt and libX11 bl3.mk
  - add patch comments

PKGREVISION -> 4.