cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/_POSIX_TIMESTAMP_RESOLUTION.c -o unistd/_POSIX_TIMESTAMP_RESOLUTION -D_POSIX_C_SOURCE=202405L  -lm -lpthread  -liconv
unistd/_POSIX_TIMESTAMP_RESOLUTION.c:3:17: error: use of undeclared identifier '_POSIX_TIMESTAMP_RESOLUTION'
    3 | int const foo = _POSIX_TIMESTAMP_RESOLUTION;
      |                 ^
1 error generated.