Fix error checks on pthread calls.

Found using valgrind.

caster/jobs.c

@@ -32,7 +32,7 @@ struct joblist *joblist_new(struct caster_state *caster) {
 		STAILQ_INIT(&this->append_jobq);
 		P_MUTEX_INIT(&this->mutex, NULL);
 		P_MUTEX_INIT(&this->append_mutex, NULL);
-		if (pthread_cond_init(&this->condjob, NULL) < 0)
+		if (pthread_cond_init(&this->condjob, NULL) != 0)
 			caster_log_error(this->caster, "pthread_cond_init");
 	}
 	return this;
@@ -74,7 +74,7 @@ void joblist_free(struct joblist *this) {
 	P_MUTEX_UNLOCK(&this->mutex);
 	P_MUTEX_DESTROY(&this->mutex);
 	P_MUTEX_DESTROY(&this->append_mutex);
-	if (pthread_cond_destroy(&this->condjob) < 0)
+	if (pthread_cond_destroy(&this->condjob) != 0)
 		caster_log_error(this->caster, "pthread_cond_signal");
 	free(this);
 }
@@ -149,7 +149,7 @@ void joblist_run(struct joblist *this) {
 				/*
 				 * All queues empty => wait.
 				 */
-				if (pthread_cond_wait(&this->condjob, &this->mutex) < 0)
+				if (pthread_cond_wait(&this->condjob, &this->mutex) != 0)
 					caster_log_error(this->caster, "pthread_cond_wait");
 				continue;
 			}
@@ -339,7 +339,7 @@ static void _joblist_append_generic(struct joblist *this, struct ntrip_state *st
 	/*
 	 * Signal waiting workers there is a new job.
 	 */
-	if (pthread_cond_signal(&this->condjob) < 0)
+	if (pthread_cond_signal(&this->condjob) != 0)
 		caster_log_error(this->caster, "pthread_cond_signal");
 	P_MUTEX_UNLOCK(&this->append_mutex);
 }