bug#50972: src/ls.c fails to build when __GNUC_PREREQ is not defined (e.g., OpenBSD)

[Pádraig Brady]

On 03/10/2021 03:07, Paul Eggert wrote:
> On 10/2/21 7:44 AM, Brian Callahan wrote:
> > Once this fix is done, the rest of coreutils-9.0 builds and works OK.
>
> Thanks for letting us know, as it's been a while since I tried building
> coreutils on OpenBSD. I just now tried it on OpenBSD 6.9 and found some
> other problems that were easy to lose sight of in the blizzard of false
> alarms that clang emits on OpenBSD 6.9. I fixed all the problems I
> noticed and installed the following patches into coreutils:
>
> https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=4cfd48481da0486e2bad193495bc38e7d5ead7e4
> https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=b31a6a09ad0caddce29729f8c9bc4c36c073b7b6
> https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=5b43b8e9ce215864001314f92097584bceb71b58
>
> These rely on the following OpenBSD-related patches to Gnulib, which I
> installed earlier today:
>
> https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=9bcd248da1ef25b3ff3431248f53401e1123d74f
> https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=dd0af10fa597a95ffe5f4f110ef5edefc2f680bc
>
> The first patch listed above should fix the problem you mentioned; you
> might want to look at the other patches as well.
>
> By the way, how do you deal with all those false positives from clang?
> Do you suppress them with CFLAGS? I'm referring to the many warnings
> like "comparison is always true due to limited range of data type" and a
> few "integer overflow in expression" warnings. With so many false alarms
> I wouldn't be surprised if people stopped paying attention to compiler
> warnings even if they're valid.

Thanks for doing all that.
I'm confused as to why some functions need _Noreturn and some don't.
For example why does cleanup_fatal() in csplit.c need it since it calls exit()?
Does GCC not propagate the noreturn from exit to cleanup_fatal()?

In general I see this may introduce warnings on older systems,
but that's fine as dev is generally done on newer compilers,
and non dev builds on older systems will not have -Werror set.

thanks,
Pádraig