[bug#41286] check for argp header

[bug#41286] check for argp header

[Nikita Gillmann]

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Hi,

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.

I haven't tested this, but semantically it should check out. I don't
know how much changed in guix's bootstrap but configure.ac should still be
the right place for this patch. 

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From eb8214d2cd6b2170f6e05b89dbd8e47e1f0f4326 Mon Sep 17 00:00:00 2001
From: nikita <nikita@n0.is>
Date: Fri, 15 May 2020 14:23:48 +0200
Subject: [PATCH] configure: check for arpg header as required by nix.

This is provided by glibc, porting to a platform without glibc
revealed this lack of check.
---
 configure.ac | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/configure.ac b/configure.ac
index 0a20b476eb..174633785a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -266,6 +266,9 @@ else
 fi
 AC_SUBST([LIBLZ])
 
+# check for standard headers, required in Nix daemon
+AC_CHECK_HEADERS([argp.h])
+
 dnl Check for Guile-SSH, for the (guix ssh) module.
 GUIX_CHECK_GUILE_SSH
 AM_CONDITIONAL([HAVE_GUILE_SSH],
-- 
2.25.2

[bug#41286] check for argp header

[Ludovic Courtès]

Hi Nikita,

Nikita Gillmann <nikita@n0.is> 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’.