Re: FAIL: test-vasprintf-posix failure on darwin12 cause

[Eric Blake]

On 06/28/2013 11:51 AM, Jack Howarth wrote:
> Eric,
>    I am not having any luck with the bootstrap working if I do...
> 
> git clone git://git.savannah.gnu.org/m4.git
> cd m4
> bootstrap
> 
> It fails with...
> 
> Makefile.am:152: error: 'pkglibexecdir' is not a legitimate directory for 
> 'LTLIBRARIES'

Uggh, I'll have to figure out if I can reproduce that.  Newer automake
is getting picker than older automake.

> 
> This is against fink's autoconf 2.69 and automake 1.12. Can you email me a 
> tarball of
> the regenerated m4 trunk directory?

Yes, although it may be a few days (I'm still recovering from inbox
shock after a 3-week vacation :)

>             Jack
> ps Jeremy Huddleston Sequoia at Apple had the following observations...
> 
> -------------------------------------------------------------------------------------------------------------------------
> The fact that result=0 is a good thing.  That conftest is producing a bitmask 
> of bugs it hit.  In the case of Snow Leopard,
> +it hit:
> 
> And on Lion, it just hits the result=4 case
> ---------------------------------------------------------------------------------------------------------------------------
> It looks like they're trying to catch the same bug as conftest.c but chose 
> %.0a which revealed something different.
> 
> If we change 1.51 to 1.52, it passes … so this looks like a rounding issue.

An incorrect rounding issue - so the gnulib autoconf test is too weak to
filter out the latent rounding bug once all the other MacOS bugs have
been fixed by upgrading to darwin12.

> 
> I'd recommend changing the m4 test from 1.51 to 1.52 and then possibly adding 
> another check for this rounding bug if that
> +matters to them.

It DOES matter, since POSIX requires that %.0a obey current rounding
rules; in fact, I think this issue has already been discussed on the
gnulib lists, and that patches have already been proposed there that
indeed add a stricter configure-time test to check for incorrect
rounding, although I couldn't (quickly) find a URL to that discussion
while writing this email.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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