#define SvGROW(sv,len) (SvLEN(sv) < (len) ? sv_grow(sv,len) : SvPVX(sv))
#define Sv_Grow sv_grow
-#ifdef USE_THREADS
-# define FDPID_LOCK() MUTEX_LOCK(&PL_fdpid_mutex)
-# define FDPID_UNLOCK() MUTEX_UNLOCK(&PL_fdpid_mutex)
-#else
-# define FDPID_LOCK()
-# define FDPID_UNLOCK()
-#endif