cc -pthread   -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations sys_socket/SO_PROTOCOL.c -o sys_socket/SO_PROTOCOL -D_POSIX_C_SOURCE=202405L -lm -lpthread  -lgdbm_compat -lintl -lnetwork -lbsd -latomic
sys_socket/SO_PROTOCOL.c:2:17: error: 'SO_PROTOCOL' undeclared here (not in a function)
    2 | int const foo = SO_PROTOCOL;
      |                 ^~~~~~~~~~~