ports/158179: some packages do not fully honor -P dir option in pkg_add(1)

[Stephen Montgomery-Smith]

I was looking through the source code of pkg_add.  Personally I don't 
see how the "-P" or "-p" option could be made to work with pkg_add. 
Many of the installation commands involve scripts which have ${PREFIX} 
hard coded into them.  ${PREFIX} is often hard coded when trhe package 
is created by the port.  In my opinion, the options "-p" and "-P" should 
be removed from pkg_add.

Either that, or provide the port a way to access "@cwd" in any scripts 
it installs.  But this would require a major overhaul of the whole ports 
system, and probably much of the software it installs as well.

Am I missing something?

Stephen