Make it so that the line numbers indent reports are the real line
numbers (currently it is often off by a few).

Error recover should probably be enhanced.  At a minimum, "indent
foo.c" should not overwrite foo.c when it gets an error.  Fancy error
recover is probably not worth the effort because indent is pretty
fast.  Stopping after the first error might be more helpful than the
current error cascades.

Also, there is a bug in that indent flags the following as illegal:
enum bar { a = 1, b = 2 };

Make the -nss option cause
  while (foo)
    ;
This is the real alternative to
  while (foo) ;

Look at all the undocumented options, and determine which of them are
bug-free enough that they should be documented.

Look at termcap interface from Berkeley (and other recent enhancements
not in 4.3-tahoe) and see whether it is worth merging those changes
into our indent or our indent into Berkeley's.