Re: SETPGRP and autoconf

[Daniel Jacobowitz <dmj+@andrew.cmu.edu>]

On Thu, Jul 26, 2001 at 12:40:02PM +0200, Mark Kettenis wrote:
>    Date: Wed, 25 Jul 2001 16:24:20 -0700
>    From: Daniel Jacobowitz <dmj+@andrew.cmu.edu>
> 
>    I should have objected :)  But it'd been so long since I last saw this issue
>    that I forgot about it.
> 
>    AC_FUNC_SETPGRP has some regrettable problems.  Witness:
> 
>    checking whether setpgrp takes no argument... configure: error: cannot check
>      setpgrp if cross compiling
> 
>    Thus breaking all host-x-host cross builds.
> 
> Bugger!

Got my reaction in one.

>    This is what I really hate about autoconf.  There's no good reason for
>    AC_FUNC_SETPGRP to be an executed test.  If you have a prototype for
>    setpgrp(void),  setpgrp(1,1) won't compile, and you don't need to execute
>    anything at all.
> 
> Who says you've got a prototype?  Even though GDB requires an ISO C
> compiler now, this doesn't mean the host's headers have to be ISO
> C-compliant.

Ugh.

>    What can we do about this?  Besides my usual hack: I have a huge list of
>    autoconf cache variables in my build environment, preset.
> 
> Dunno.  I don't think there are too many people cross-compiling GDB.
> If we want to fix this, we could use an alternative check for
> AC_FUNC_SETPGRP when cross-compiling based on the setpgrp prototype.
> I don't think it would hurts not defining SETPGRP_VOID if no
> prototypes are available, since passing the extra arguments should be
> harmless.

Even if we don't require ISO C headers when building, requiring them
while cross-compiling doesn't seem too unreasonable.  I'll try to work
up a patch for this.

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer