Coming XEmacs package building changes

[I'm working towards a goal of removing the GNU make dependency in building the XEmacs Lisp tree from source, but it won't go very fast.] There are now methods of installing executable scripts (but not binaries) from lisp packages. Name them with $(LIBSRC_FILES). The many binkit-* rules have been obsoleted by a single binkit-common rule. The Gnats and Tm scripts have been removed for the next XEmacs releases. The `mmencode' binary remains because I don't have a good silver bullet to kill it with. As Hrvoje has pointed out, etags/ctags/ootags/etags.el needs to be packaged too, but they will require very specialized support beyond basic binary building. I haven't begun to deal with this issue, but welcome suggestions. Setting $(STAGING) to something appropriate and commenting out $(MAKE_TARBALLS) should now work as a `make install' into a live XEmacs package lisp tree. I'm going to get these changes checked in by sometime late tomorrow evening (US/Pacific) after I have completed testing them.