_PROP_MUTEX_DECL_STATIC
_PROP_MUTEX_DECL_STATIC(_prop_number_tree_mutex)
#define _PROP_MUTEX_DECL_STATIC(x) static kmutex_t x;
#define _PROP_MUTEX_DECL_STATIC(x) /* nothing */
#define _PROP_MUTEX_DECL_STATIC(x) static mutex_t x;
#define _PROP_MUTEX_DECL_STATIC(x) /* nothing */
#define _PROP_MUTEX_DECL_STATIC(x) static pthread_mutex_t x;