Build fails when compiling with `-Wincompatible-pointer-types` (GCC 15)

[heijligen]

when compiling why3 as part of spark2014 the build fails when compiling with -Wincompatible-pointer-types.

spark2014 branch: fsf-15
gcc/gnat: 15.1.0
OS: Linux / NixOS unstable

gnatprove> src/server/cpulimit-unix.c: In function 'main':
gnatprove> src/server/cpulimit-unix.c:95:23: error: assignment to '__sighandler_t' {aka 'void (*)(int)'} from incompatible pointer type 'void (*)(void)' [-Wincompatible-pointer-types]
gnatprove>    95 |         sa.sa_handler = &wallclock_timelimit_reached;
gnatprove>       |                       ^
gnatprove> src/server/cpulimit-unix.c:45:6: note: 'wallclock_timelimit_reached' declared here
gnatprove>    45 | void wallclock_timelimit_reached() {
gnatprove>       |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
gnatprove> In file included from src/server/cpulimit-unix.c:22:
gnatprove> /nix/store/r25srliigrrv5q3n7y8ms6z10spvjcd9-glibc-2.40-66-dev/include/signal.h:72:16: note: '__sighandler_t' declared here
gnatprove>    72 | typedef void (*__sighandler_t) (int);
gnatprove>       |                ^~~~~~~~~~~~~~
gnatprove> Ocamlopt src/util/cmdline.ml
gnatprove> make[1]: *** [Makefile:810: src/server/cpulimit-unix.o] Error 1

This could be fixed with:

diff --git a/src/server/cpulimit-unix.c b/src/server/cpulimit-unix.c
index 1cf8880ee..079bb4efd 100644
--- a/src/server/cpulimit-unix.c
+++ b/src/server/cpulimit-unix.c
@@ -42,7 +42,7 @@ void show_time() {
   }
 }
 
-void wallclock_timelimit_reached() {
+void wallclock_timelimit_reached(int unused) {
   fprintf(stderr,
           "Why3cpulimit: wallclock timelimit %d reached, killing command\n",
           wallclock_timelimit);

Sorry for only creating an issue not not directly a pull request. Building or testing spark2014 master is not possible for me

[kanigsson]

Thanks for your report. Upstream already has a fix for it. For fsf-15 branch I am going to cherry-pick the fix (by the way this will change the submodule commit again 😉 ). For master we will get this fix on our next merge.