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

[Paul Eggert]

On 10/3/21 4:38 AM, Pádraig Brady wrote:
> I'm confused as to why some functions need _Noreturn and some don't.

Yes, it's a bit of a pain. _Noreturn is useful on extern functions, 
since otherwise GCC typically won't know the function doesn't return. On 
static functions, though, _Noreturn generally isn't needed since GCC can 
figure it out.

Unfortunately, I needed to keep _Noreturn on three static functions in 
Coreutils to pacify GCC into not generating the following false alarms. 
Today I reported this issue as GCC bug 102578 
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102578>.

  src/csplit.c: In function 'xalloc_die':
  src/csplit.c:235:1: error: 'noreturn' function does return [-Werror]
    235 | }
        | ^

  src/sort.c: In function 'open_temp':
  src/sort.c:1206:7: error: this statement may fall through 
[-Werror=implicit-fallthrough=]
   1206 |       async_safe_die (errno, "couldn't execute compress 
program (with -d)");
        | 
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  src/sort.c:1208:5: note: here
   1208 |     default:
        |     ^~~~~~~

  src/test.c: In function 'find_int':
  src/test.c:161:1: error: control reaches end of non-void function 
[-Werror=return-type]
    161 | }
        | ^