gengtype-{lex,yacc}.c rules broken

[DJ Delorie]

> Seems an opportune moment to point out that there have been 8.3
> violations in the testsuite ever since we switched to four-digit year
> numbers,

This we can accept.

> and also that there's ~300 lines of poorly tested crap in cpplib
> that exists only to support 8.3 filenames at runtime (not build
> time).

Ah, *runtime* 8.3 issues are still important to us.

And you'd be surprised how much stuff gets tested without us hearing
about it ;-)