cc -O2 -pipe -pthread -I/usr/local/include  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations fcntl/S_IRGRP.c -o fcntl/S_IRGRP -D_POSIX_C_SOURCE=202405L  -lm -lpthread -lrt -L/usr/local/lib  -lintl -lstdthreads -lcrypt
fcntl/S_IRGRP.c:3:2: error: "S_IRGRP is not defined"
    3 | #error "S_IRGRP is not defined"
      |  ^
1 error generated.