_PROP_RWLOCK_DECL
#define _PROP_RWLOCK_DECL(x) krwlock_t x ;
#define _PROP_RWLOCK_DECL(x) /* nothing */
#define _PROP_RWLOCK_DECL(x) rwlock_t x ;
#define _PROP_RWLOCK_DECL(x) /* nothing */
#define _PROP_RWLOCK_DECL(x) pthread_rwlock_t x ;