etc/Makefile cleanup

[Matthew Dillon]

    Hmm.  Well, most of those conditionals are there to make sure that
    a make upgrade does not turn the system into an unbootable brick
    if run on too-old a copy of the world.

    A lot of them are really old and can be removed, but I think a cleanup
    needs some additional checks to really make it a good cleanup:

    * Adjust installworld to install a file in /etc with the release id,
      as the last step in the installworld operation.  Maybe call it
      /etc/.release or something.

    * Add logic to make upgrade to check for the existance of and the
      contents of {DESTDIR}/etc/.release.  This allows make upgrade to know
      definitively what version of the DragonFly world was last installed.
      If it's too old, make upgrade can bail out with an error message.

    Also, the .inc file should be named Makefile_<something>.inc, not
    FilesToRemove.inc.

    Apart from that it looks good.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>