put mystery line back but !WIN32

put mystery line back but !WIN32

Since that line of code is used by a lot of different ports, I decided to
recant its removal and just add #ifdef to ensure it isn't compiled on WIN32.

I think other ports might encounter the same issue where the first pass with
filename set to 'sysconf', is then going to overwrite the hard-coded user
config file name, but I can't fix or test those so for those ports, it
will be now be back the way it was.