Re: Gmp test failure on armhf

[Mark H Weaver <mhw@netris.org>]

Andreas Enge <andreas@enge.fr> writes:

> On Sun, Jun 28, 2015 at 10:39:32PM +0200, Ludovic Courtès wrote:
>> Could you post the relevant excerpt of the build log, or
>> ‘test-suite.log’?
>
> Well, I tried to build it by hand, and it worked; then I tried again with
> a recent git version, and it also worked.
>
> Since I noticed a "FIXME" in the gmp package, I worked on that. The
> attached patch backports a fix to config.guess in the gmp trunk that 
> correctly detects the neon architecture on multicore arm machines, instead
> of explicitly passing the build triplet.

We shouldn't be using config.guess anyway, because we shouldn't be
compiling packages specialized for the build machine, at least not by
default.

A while back on IRC, Ludovic agreed to my proposal to pass --build to
configure by default in gnu-build-system, a change to be made hopefully
in the next core-updates cycle.  After that, config.guess will not be
used.

As for NEON, I had originally followed Debian's armhf decision to
compile code that doesn't require NEON support, but have since changed
my mind about that.  It seems that the Debian porters made that decision
to support a couple of hardware devices that may have been important at
the time, but that time has passed.  I've since learned that NEON is a
common target for modern highly optimized ARM assembly code, and that we
should assume it as a baseline.  This is another change that I think we
should make in the next core-updates cycle.  To give credit where credit
is due: John Darrington chose to target NEON in his initial patches for
Guix armhf.

If we make these changes, then I think this patch is superfluous, right?

     Mark