73331b68a9
Fixes http://autobuild.buildroot.net/results/2058934e442c0b3f3d0bd81bd7ed080c2eaade31/ The source code uses empty argument function pointer prototypes, which changed behaviour in C23 (default in gcc-15): https://gcc.gnu.org/gcc-15/porting_to.html#c23-fn-decls-without-parameters Causing build issues. Fix it by forcing gnu99 mode instead. Signed-off-by: Peter Korsgaard <peter@korsgaard.com>