cc -pthread   -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/_XOPEN_REALTIME_THREADS.c -o unistd/_XOPEN_REALTIME_THREADS -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt  -lgdbm_compat -lcrypt -latomic
unistd/_XOPEN_REALTIME_THREADS.c:9:2: error: #error "_XOPEN_REALTIME_THREADS is not defined"
    9 | #error "_XOPEN_REALTIME_THREADS is not defined"
      |  ^~~~~