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/8476059/

whereas my test build with GCC 14 succeeded:
https://copr.fedorainfracloud.org/coprs/dmalcolm/gcc-15-smoketest-3.failed.checker/build/8477617/

Looking at the failure logs e.g.
https://download.copr.fedorainfracloud.org/results/dmalcolm/gcc-15-smoketest-3.failed/fedora-rawhide-x86_64/08476059-abcm2ps/builder-live.log.gz
I see:

format.c: In function 'interpret_fmt_line'
format.c:1161:29: error: two or more data types in declaration specifiers
 1161 |                         int bool;
      |                             ^~~~
format.c:1161:25: warning: useless type name in empty declaration
 1161 |                         int bool;
      |                         ^~~

This is probably due to GCC 15 now defaulting to -std=gnu23, whereas GCC 14 defaulted to -std=gnu17: 'bool' is a keyword in C23.  It's probably fixable by renaming this variable (or by manually adding -std=gnu17 to the C build flags)


Reproducible: Always