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