1) Fixed a bug where XQUARTZ was #defined when auto but not when --enable-xquartz
2) Cleaned up missing #includes and function prototypes.
3) Fixed some invalid C syntax problems
4) Removed a bunch of dead code
5) Cleaned up code to prevent some warnings
6) Bugfix in xpr/x-hook.c - looks like someone just forgot to finish writing code for hook_remove()... I only noticed it because gcc -Wall complained about reaching the end of a non-void function... lucky for us gcc is smarter than we are.
change "foo.h" to <X11/foo.h> for core headers, e.g. X.h, Xpoll.h;
change "foo.h", "extensions/foo.h" and "X11/foo.h" to
<X11/extensions/foo.h> for extension headers, e.g. Xv.h;
change "foo.[ch]" to <X11/Xtrans/foo.[ch]> for Xtrans files.