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/8476068/

whereas my test build with GCC 14 succeeded:
https://copr.fedorainfracloud.org/coprs/dmalcolm/gcc-15-smoketest-3.failed.checker/build/8477634/

Looking at the failure logs e.g.
https://download.copr.fedorainfracloud.org/results/dmalcolm/gcc-15-smoketest-3.failed/fedora-rawhide-x86_64/08476068-aime/builder-live.log.gz
I see:

a1-l.s.c: In function ‘beta_call’:
a1-l.s.c:171:21: error: expected identifier or ‘(’ before ‘true’
  171 |                 int true;
      |                     ^~~~
a1-l.s.c:178:22: error: lvalue required as left operand of assignment
  178 |                 true = link_data->variable.type;
      |                      ^


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


Reproducible: Always