cc -O2 -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations dirent/dirfd.c -o dirent/dirfd -D_POSIX_C_SOURCE=202405L  -lm -lpthread -lrt  -lintl -lcrypt
dirent/dirfd.c:5:21: error: 'dirfd' undeclared here (not in a function)
    5 | int (*foo)(DIR *) = dirfd;
      |                     ^~~~~