Given that DJGPP 2.02 was released in 1998, may I remove the two files which are added to support earlier releases, that is:

msdos/is_exec.c
msdos/sigaction.c

? They come with a licensing exception, its explanation, and notes in other files (e.g. admin/notes/copyright) that maintainers not concerned with the MS-DOS port may have to read. This therefore removes a small bit of unnecessary clutter. My patch touches the following files:

admin/authors.el
admin/notes/copyright
etc/PROBLEMS (the problems no longer exist!)
make-dist
msdos/INSTALL
msdos/README

as well as the two removed files. No code (other than make-dist) is affected, as the method of using them was entirely reliant on manual intervention (the instructions said to compile and link the files into the Emacs executable).