cc -pthread   -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/_POSIX2_FORT_RUN.c -o unistd/_POSIX2_FORT_RUN -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt  -lgdbm_compat -lcrypt -latomic
unistd/_POSIX2_FORT_RUN.c:4:2: error: #error "_POSIX2_FORT_RUN is not defined"
    4 | #error "_POSIX2_FORT_RUN is not defined"
      |  ^~~~~