Add a pthread_cleanup compatible function to release a pthread_rwlock.

common.c

@@ -1725,6 +1725,8 @@ void mutex_cleanup(void *arg) {
 
 void mutex_unlock(void *arg) { pthread_mutex_unlock((pthread_mutex_t *)arg); }
 
+void rwlock_unlock(void *arg) { pthread_rwlock_unlock((pthread_rwlock_t *)arg); }
+
 void thread_cleanup(void *arg) {
   debug(3, "thread_cleanup called.");
   pthread_t *thread = (pthread_t *)arg;

common.h

@@ -495,6 +495,7 @@ uint16_t bind_UDP_port(int ip_family, const char *self_ip_address, uint32_t scop
 
 void socket_cleanup(void *arg);
 void mutex_unlock(void *arg);
+void rwlock_unlock(void *arg);
 void mutex_cleanup(void *arg);
 void cv_cleanup(void *arg);
 void thread_cleanup(void *arg);