cc -O2 -pipe -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations semaphore/sem_clockwait.c -o semaphore/sem_clockwait -D_POSIX_C_SOURCE=202405L  -lm -lpthread -lrt  -lstdthreads -lcrypt
semaphore/sem_clockwait.c:5:29: error: type specifier missing, defaults to 'int'; ISO C99 and later do not support implicit int [-Werror,-Wimplicit-int]
    5 | int (*foo)(sem_t *restrict, clockid_t, const struct timespec *restrict) = sem_clockwait;
      |                             ^
      |                             int
semaphore/sem_clockwait.c:5:75: error: use of undeclared identifier 'sem_clockwait'
    5 | int (*foo)(sem_t *restrict, clockid_t, const struct timespec *restrict) = sem_clockwait;
      |                                                                           ^
2 errors generated.