Add to UPDATING

[Carl A. Schmidt]

Joerg mentioned that the changes I submitted should be documented in
UPDATING.  I don't have access to my source tree right now but I can
provide a list of changes:

Removed COMPAT*X options, because they don't do anything for us.
Removed CVS_UPDATE.
Removed KRB5_HOME, this is a ports-specific option.
Changed MAKE_IDEA to WANT_IDEA.
Changed MAKE_KERBEROS5 to WANT_KERBEROS.
Changed NOCRYPT to NO_CRYPT.
Changed NOGAMES to NO_GAMES.
Changed NOLIBC_R to NO_LIBC_R.
Changed NOSHARE to NO_SHARE.
Added WANT_GCC40 (Simon Schubert did this, but it ought to be
documented).
-- 
Carl Schmidt
carl at xxxxxxxxxxxxxxx