in xv6 system

i have a program in c that shows process state, but after i change Makefile, it not working, what i missed?

this is the code called pstate.c

#include "types.h"

#include "stat.h"

#include "user.h"

int main(void) {

struct proc *p;

for (p = ptable.proc; p

if (p->state == UNUSED) {

continue;

}

printf("%d %s ", p->pid, states[p->state]);

}

exit();

}

this is the error