cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations semaphore/sem_open.c -o semaphore/sem_open -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -liconv
semaphore/sem_open.c:5:41: error: ‘sem_open’ undeclared here (not in a function)
    5 | sem_t *(*foo)(const char *, int, ...) = sem_open;
      |                                         ^~~~~~~~