[enhancement] proposal - make all ports independent of which version of Perl is installed or the major one

[Eric Cronin]

>> 3) hard to take decisions on when to upgrade the 5-<extensions>
> 
> Variants and subports would make this easier in the future. There would be little/no resistance for adding a variant or subport for a newer perl.
> 
> 
> The current perl5.12 ports work well for me so I will leave further discussion on this subject to those with better ideas and more passion for perl then I.

One thing this work does is  provides a way to potentially change a single line *in each portfile* (and revbump and test!) when upgrading perl versions.  Some portfiles have the versions hard coded quite a few times, in dependencies, in sed regexes, etc.  That part might be worth committing now with 5.12 as the value which wouldn't require any revbump to the existing ports.  It could potentially even be done in such a way that you could override that from the command line like we unsupportedly do the compiler, which would let Bjarne do what he wants, but would make it pretty clear you're in shooting yourself in the foot territory...

It's still 70 some ports that each have to have 2 lines changed to go to a new perl, but really the maintainer ought to be building and testing the port with that new version of perl before committing such a change, so I don't think that's too much.  A more official policy of what the current default version of perl is and concerted effort to test and update all ports within a short window would cut down on the window where you need multiple versions of perl and modules installed just as a dependency for things.  If py*->py27 is any indication the current system doesn't promote a quick updating.

Thanks,
Eric