tv@pobox.com said:
> The proper fix would be to .NOPATH: the respective .c (and .h, if
> applicable) file(s), so that yacc *will* be invoked (and will place
> the new file in ${.OBJDIR}). 

I've just tried this and found that standard yacc can't process
the .y file (%pure_parser).

I've also tried to avoid the yacc invocation by:
${DIST}/lib/getdate.c: .MADE
and
.MADE: ${DIST}/lib/getdate.c
Neither of them worked as expected.
(.MADE seems to work in other parts of the tree - don't know
what's going on here...)

> This sort of thing has been done elsewhere in the tree (gcc comes to mind
> 8-).

Hmm...
gnu/usr.bin/gcc/Makefile.backend:
[...]
# Don't auto-frob .y or .l files.
.l.c .y.c .y.h:
	@true

best regards
Matthias