cc -O2 -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  -lintl -lcrypt
unistd/_POSIX2_FORT_RUN.c:4:2: error: #error "_POSIX2_FORT_RUN is not defined"
    4 | #error "_POSIX2_FORT_RUN is not defined"
      |  ^~~~~