First attempt at unifying WITH_* options

[Philip Reynolds]

Richard Coleman <richardcoleman at mindspring.com> 86 lines of wisdom included:
> I want to voice my support for adding this type of facility to the port 
> system for FreeBSD.  This is sorely needed.
> 
> I haven't tried the patch yet.  But from a brief glance, it apppears to 
> be exactly what we need.
> 
> We also need a place for the port maintainer to record a summary of the 
> options, as well as any comment that is specific to that option and 
> port.  For instance, if each port had a file "pkg-options", this could 
> print:
> 
> make print-option
>     WITH_TCL - Add tcl support.  Currently experimental.
>     WITH_TK  - Add tk support.  Currently broken.
>     WITH_FOO - Add support for foo.  Developers only.

I hate me too replies, but this seems like definately one of the
biggest shortfalls I've seen with the ports system. It also means
ports can be harder to batch build because they can ignore creating
command-line options and merely allow options handed to the user by
some GUI tool, like dialog(1).
-- 
Philip Reynolds                      | RFC Networks Ltd.
philip.reynolds at rfc-networks.ie      | +353 (0)1 8832063
http://people.rfc-networks.ie/~phil  | www.rfc-networks.ie