I'm experimentally rebuilding rawhide with the not-yet-released GCC 15 to see if anything breaks, and to help write the porting guide.  See https://fedoraproject.org/wiki/User:Dmalcolm/gcc-15

My test build with GCC 15 failed:
https://copr.fedorainfracloud.org/coprs/dmalcolm/gcc-15-smoketest-3.failed/build/8476065/

whereas my test build with GCC 14 succeeded:
https://copr.fedorainfracloud.org/coprs/dmalcolm/gcc-15-smoketest-3.failed.checker/build/8477626/

Looking at the failure logs e.g.
https://download.copr.fedorainfracloud.org/results/dmalcolm/gcc-15-smoketest-3.failed/fedora-rawhide-x86_64/08476065-adjtimex/builder-live.log.gz

I see:

adjtimex.c: In function ‘log_times’:
adjtimex.c:1415:7: error: too many arguments to function ‘failntpdate’
 1415 |       failntpdate("cannot find ntpdate");
      |       ^~~~~~~~~~~
adjtimex.c:188:13: note: declared here
  188 | static void failntpdate();
      |             ^~~~~~~~~~~

This is probably due to GCC 15 now defaulting to -std=gnu23, whereas GCC 14 defaulted to -std=gnu17, and C23 is stricter about function prototypes than C17.  It's probably fixable by fixing the function prototypes (or by manually adding -std=gnu17 to the C build flags)


Reproducible: Always