mailman attempting to reinstall postfix and other oddities

[Roger Marquis]

Have a working and patched mailman but the port build is running into all
sorts of issues.  First it's warning me about the PYTHON_DEFAULT_VERSION,
which is apparently 2.6 though 2.7 is installed and neither are set in
make.conf:

  /!\ WARNING /!\
  Your requested default python version 2.7 is different from the installed default python interpreter version 2.6

(whose idea was the "/!\" anyway?).  Ignoring that warning it next
attempts to reinstall postfix which is already at the current version:

   ===>   postfix-base-2.11.4,1 is already installed
       You may wish to ``make deinstall'' and install this port again
       by ``make reinstall'' to upgrade it properly.
       If you really wish to overwrite the old port of postfix-base
       without deleting it first, set the variable "FORCE_PKG_REGISTER"
       in your environment or the "make install" command line.

(why doesn't make automatically "deinstall reinstall" or, better yet,
leave it alone?  The suggestion to set FORCE_PKG_REGISTER should also
be deprecated IMO.)  Then it goes on to have issues installing (not
compiling) py-dnspython... all on 8.4 (please, no recommendations to
workaround by upgrading to 9 or 10 while 8.4 is supported).

Can't recall seeing these issues before portsng/pkgng so am putting this
out for recommendations.

Roger Marquis