[rfa] update config/djgpp/fnchange.lst with recent gdb.c++ files

[Michael Elizabeth Chastain]

Eli Z writes:
> Changes to fnchange.lst that add files in gdb.c++ are indeed obvious.

OK thanks.  As gdb.c++ maintainer I will make sure that fnchange.lst
gets all the new files.

> Since the ARI script processes fnchange.lst before it runs doschk and
> reports file names that are invalid on DOS 8+3 filesystems, I think
> just rerunning ARI should be a sufficient test.  Andrew, is that true?

I can't find the source code for ARI.  I suspect that it's in the
gdbadmin module but I ran into a CVS error when I tried to check it out.
(I reported a PR on that).

Michael C