yacc/lex name conflicts

[Christian Csar]

Is there anyway to control the behavior of ylwrap? The project I am
converting has its parsers use files like foo.l and foo.y for the lex
and yacc files as they go together, and automake then converts both of
these to foo.c, overwriting the first seemingly silently. Admittedly I
solved this by changing foo.l to foo-lex.l, but it seems rather
inelegant. If there is a to notice the existence of foo.l and foo.y in
the same directory, it might be worth printing out a message as it is
not an immediately obvious problem (except for refusing to build).

Christian