33854: errors end recursion through scanner()

Makes **/ more easily interruptible
33894: boundary conditions in unmeta(), unmetafy()

Check that we aren't running off the end of the string when converting the
next byte after a Meta byte.  This is just defensive programming in case
of bad metafied strings coming through from gettokstr(), some repairs
there are likely still needed.
33901: fix warning message reference to funcstack (updates 33859)
33912: fix filename default case

version-of-od argument list manipulation clobbered the default spec