Relax source file handling on command line
Relax source file handling on command line

Allow multiple source files on command line, and allow them to be
after (or even interspersed) with options to better match modern
Unix conventions.

Multiple source files is mainly to allow specifying a single byte
character set mapping via a file of stringdefs.

snowballstem/snowball,snowballstem/snowball,snowballstem/snowball,snowballstem/snowball,snowballstem/snowball,snowballstem/snowball,snowballstem/snowball,snowballstem/snowball