[bug#41286] check for argp header

[Ludovic Courtès]

Hi Nikita,

Nikita Gillmann <address@hidden> skribis:

> as mentioned in IRC I have begun porting Guix to NetBSD (with the path
> taken not yet decided upon, just plain building guix itself for now).
>
> Glibc provides argp. Arguably we don't have to check for argp because
> Guix targets glibc. But I am quiete certain that there will be people
> who will attempt to do what I am doing and run into this.

Guix targets glibc-based systems, so as you write, it’s reasonable to
assume argp is present.

Also, using AC_CHECK_HEADERS doesn’t achieve anything: it only defines
‘HAVE_ARGP_H’ to zero or one.

Last, I don’t want to discourage anyone from porting, but I also want to
be clear about what it entails.  I’m strongly in favor of supporting
only glibc because: (1) after all, it’s about GNU as a system, and (2)
my experience with Nixpkgs is that supporting multiple C libraries is
just too much work to maintain good support.

Thus I’m closing for now.

Thanks,
Ludo’.