Allow / (slash) to be used as separator with `--package-path` ...on systems where separator is different (e.g, Windows). This allows writing somewhat cross-platform scripts / makefiles (using make in Windows with MSYS2).

osx_Info.plist:
    needed for the stx.dmg (IDE APP package)

osx_Distribution:
    needed for the stx.pkg (runtime package for standalone programs)