editors/the: overhaul, resolved many existing issues

When this port was resurrected, none of the non-default options had a
prayer of working. Requirements were spelled incorrectly and
mis-specified.

First, overhaul the makefile to use modern options helpers.
Then create a Rexx group of options. Rexx must be used, but the original
intent is that it builds with Rexx/Regina by default, but optionally with
Rexx/imc. Now that this is cleaned it, it was discovered that Rexx/imc
can't build the, so leave the option but mark it broken.

Similarly, it builds with ncurses by default. This wasn't configured
properly, but now it's been fixed. A new option group called display
allows the to be built with XCurses. This was also mis-specified and
could never build anyway. Using a sed command to remove 2 (minor?)
unsupported lines, the xcurses option now builds and links to the
successfully.

Finally the xaw3d, also mispecified, doesn't dynamically link to the.
The specification was fixed and changed to the static library. The xawed
is a valid configure option but it's not clear if the static library is
actually used or not. It's off by default, as before.

This port did not receive adequate scrutiny when it was brought back
into the tree. Most of the issues listed here would have been caught
with even a cursory check.

Approved by: just-fix-it and ncurses blanket