bsd.*.mk: ruby and interpreters

1) change PERL interpreter to just use /usr/local/bin/perl.  Before
   it was specifying the exact version which would break when it gets
   updated.
2) Bump default ruby up to 1.9.  FreeBSD has been trying to get there
   for over a year now, it should have occurred already.  Let's not
   start DPorts off with ruby 18.