each one to be unsigned int (instead of int) when the type is missing.
#include "lib/pool_alloc.h"
#ifndef HAVE_ID_T
#include "lib/pool_alloc.h"
#ifndef HAVE_ID_T
+typedef unsigned int id_t;
#endif
#ifndef HAVE_PID_T
typedef int pid_t;
#endif
#ifndef HAVE_MODE_T
#endif
#ifndef HAVE_PID_T
typedef int pid_t;
#endif
#ifndef HAVE_MODE_T
+typedef unsigned int mode_t;
#endif
#ifndef HAVE_OFF_T
typedef long off_t;
#endif
#ifndef HAVE_OFF_T
typedef long off_t;