Re: [Bug-gnulib] AC_PROG_YACC

[Bruno Haible]

Derek Robert Price wrote:
> It appears that some `make's (notably some BSDs) have a default
> setting for YFLAGS (YFLAGS = -d) that some of my users are not happy
> with.  It breaks builds, notably with the GNULIB getdate package,
> which comes with its own getdate.h header (which gets overwritten by
> calls to `bison -y -d getdate.y'...).  Is this something that
> AC_PROG_YACC (or gl_BISON for the GNULIB folks) should be checking for
> and dealing with?
>
> My workaround will be to just stick a `YFLAGS=' line in my
> Makefile.am, but I thought you might like the bug report.

The automake documentation says:
  "When `yacc' is invoked, it is passed `YFLAGS' and `AM_YFLAGS'.  The
   former is a user variable and the latter is intended for the
   `Makefile.am' author."

So this means, YFLAGS is meant as a variable through which the user can
influence the compilation (like CFLAGS, CPPFLAGS, LDFLAGS etc.). By
setting it to empty, you give the user less freedom.

I'd say, since option '-d' is not appropriate in all cases, it's a mistake
to use it by default. The bug is therefore in the BSD make.

Bruno