cc -pipe -O   -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations sys_socket/SO_DOMAIN.c -o sys_socket/SO_DOMAIN -D_POSIX_C_SOURCE=202405L  -lm -lpthread -lrt  -lrt -lcrypt
sys_socket/SO_DOMAIN.c:2:17: error: 'SO_DOMAIN' undeclared here (not in a function)
 int const foo = SO_DOMAIN;
                 ^~~~~~~~~