Re: New warnings on emacs-26 branch with gcc 8.2.0

[Andy Moreton <andrewjmoreton@gmail.com>]

On Sun 05 Aug 2018, Paul Eggert wrote:

> Andy Moreton wrote:
>
>> cc1.exe: warning: -Wabi won't warn about anything [-Wabi]
>> cc1.exe: note: -Wabi warns about differences from the most up-to-date ABI, which is also used by default
>> cc1.exe: note: use e.g. -Wabi=11 to warn about changes from GCC 7
>
> I noticed this problem a while ago on Fedora in several GNU projects, and
> fixed it for Emacs master in commit 2018-06-30T00:31:04!eggert@cs.ucla.edu.

Thanks. I don't see these -Wabi warning on master.

> To avoid the problem entirely in the emacs-26 I'd run admin/merge-gnulib and
> update everything from Gnulib as it's not worth the trouble to cherry-pick
> these sorts of fixes from master. If we'd rather not do admin/merge-gnulib,
> then we can just suggest './configure --disable-gcc-warnings' and/or 'make
> WERROR_CFLAGS=' to emacs-26 developers; either of these should work around the
> problem. (Builders from tarballs needn't worry about this, as GCC warnings are
> disabled for them by default.)

That's a decision for the maintainers, but I think it would be useful to
fix this if possible.

>> Can this be simplified to be less over-zealous and less time consuming ?
> The overzealous-warning part has been fixed on master. I'm sure 'configure'
> could be sped up, if someone wants to take the time to work on that.

Of the 562 "checking" lines when running configure on master, 146 of
them are "checking whether C compiler handles -W*". This is excessively
time consuming. Can gnulib not do less work to acheive this end, or do
the work more efficiently ?

    AndyM