groff and GNU_PROGRAM_PREFIX

["Filip Hajny" <filip%joyent.com@localhost>]

The textproc/groff package currently doesn't use the GNU_PROGRAM_PREFIX 
variable at all, internally there's GROFF_COMMAND_PREFIX that could be used 
(but defaults to empty). Also, groff's configure script exhibits a behavior 
that I dislike very much: it looks for an existing 'good enough' troff 
installation, and if it finds one, it decides to force a 'g' prefix on some 
select commands (e.g. nroff) no matter what GROFF_COMMAND_PREFIX is set to.

I suggest the following change:

1. Set GROFF_COMMAND_PREFIX to the value of ${GNU_PROGRAM_PREFIX} via *_ENV 
lists.
2. Force all commands' names to adhere to #1 (removing the configure logic).

This may end up with a duplicate set of some commands (eqn, grn, indxbib, 
lookbib, neqn, nroff, pic, refer, soelim, tbl, troff), but I believe this 
should be a case of PATH and/or absolute paths anyway.

I just don't care for any builtin groff instance if I choose to use one from 
pkgsrc, and I have been using the above change on SunOS for some time.

Thoughts?

-F