fix build on darwin, which does not install include/wx-3.0/wx/unix/fswatcher_inotify.h
see comments in wxWidgets-3.0.1/build/bakefiles/files.bkl for reasons
File::Temp was first released with perl v5.6.1, so no need to install it
from pkgsrc in these days.
After four years of the update, such migration is not required anymore.