Compiling using gcc 15 fails

[hpreusse]

Compiling the project using gcc-15 fails. The following code in gregorio/gregorio-src/src/bool.h is not accepted any more. The attached patch solves the issue or me, but makes bool.h basically obsolete...

gregorio_bool.h.txt

[jakubjelinek]

bool, true and false are keywords in ISO C23, even the defines for true/false shouldn't be there at least for C23.
stdbool.h is pretty much empty header there.
Note stdbool.h has been added in ISO C99, so if the goal is also compatibility with C89 or even K&R, then there should be some fallback.
Perhaps

#if __STDC_VERSION__ >= 199901L
#include <stdbool.h>
#else
typedef unsigned int bool;
#define true 1
#define false 0
#endif

Just beware that e.g. sizeof (true) and sizeof(false) will be 1 in C23 (at least on most arches) and same as sizeof(int) in C99-C17 (and in the fallback).
And sizeof(bool) will be on most arches 1 in C99-C17 but not with the fallback (so perhaps typedef unsigned char bool; would be better).

[hpreusse]

bool, true and false are keywords in ISO C23, even the defines for true/false shouldn't be there at least for C23. stdbool.h is pretty much empty header there. Note stdbool.h has been added in ISO C99, so if the goal is also compatibility with C89 or even K&R, then there should be some fallback.

I should have stressed, that I basically wanted to report the issue and made a suggestion, which solves the issue for me. If you need to build code, which needs to be more backward compatible, please do so. Unfortunately I'm not a C programmer, hence I don't have further suggestions. Sorry!