cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations sched/pid_t.c -o sched/pid_t -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -liconv
sched/pid_t.c:3:1: error: unknown type name ‘pid_t’
    3 | pid_t* foo;
      | ^~~~~