cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations sys_time/fd_set.c -o sys_time/fd_set -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -liconv
sys_time/fd_set.c:8:1: error: unknown type name ‘fd_set’
    8 | fd_set* foo;
      | ^~~~~~