port1.0/portmain.tcl: Include information about the current OS platform and version in debug output, closes https://trac.macports.org/ticket/18435
port1.0/portmain.tcl:
Include information about the current OS platform and version in debug output,
closes https://trac.macports.org/ticket/18435

git-svn-id: 620571fa9b4bd0cbce9a0cf901e91ef896adbf27@46669 d073be05-634f-4543-b044-5fe20cf6d1d6

macports/macports-base,macports/macports-base,danchr/macports-base,danchr/macports-base,neverpanic/macports-base,neverpanic/macports-base