`.app-file STRING'
==================

   `.app-file' tells `as' that we are about to start a new logical
file.  STRING is the new file name.  In general, the filename is
recognized whether or not it is surrounded by quotes `"'; but if you
wish to specify an empty file name is permitted, you must give the
quotes-`""'.  This statement may go away in future: it is only
recognized to be compatible with old `as' programs.