Fix overly broad HAVE_PTHREAD_CANCEL compile guard.

Closes #1547. Thanks to Markus Gothe.

ChangeLog.txt

@@ -26,6 +26,7 @@ Broker:
 - Fix potential memory leaks. Closes #1773. Closes #1774.
 - Fix clients not receiving messages after a previous client with the same
  client ID and positive will delay interval quit. Closes #1752.
+- Fix overly broad HAVE_PTHREAD_CANCEL compile guard. Closes #1547.
 
 Client library:
 - Improved documentation around connect callback return codes. Close #1730.

lib/loop.c

@@ -256,7 +256,9 @@ int mosquitto_loop_forever(struct mosquitto *mosq, int timeout, int max_packets)
 
  while(run){
  do{
+#ifdef HAVE_PTHREAD_CANCEL
  pthread_testcancel();
+#endif
  rc = mosquitto_loop(mosq, timeout, max_packets);
  }while(run && rc == MOSQ_ERR_SUCCESS);
  /* Quit after fatal errors. */
@@ -281,7 +283,9 @@ int mosquitto_loop_forever(struct mosquitto *mosq, int timeout, int max_packets)
  return rc;
  }
  do{
+#ifdef HAVE_PTHREAD_CANCEL
  pthread_testcancel();
+#endif
  rc = MOSQ_ERR_SUCCESS;
  state = mosquitto__get_state(mosq);
  if(state == mosq_cs_disconnecting || state == mosq_cs_disconnected){

lib/thread_mosq.c

@@ -34,7 +34,7 @@ void *mosquitto__thread_main(void *obj);
 
 int mosquitto_loop_start(struct mosquitto *mosq)
 {
-#if defined(WITH_THREADING) && defined(HAVE_PTHREAD_CANCEL)
+#if defined(WITH_THREADING)
  if(!mosq || mosq->threaded != mosq_ts_none) return MOSQ_ERR_INVAL;
 
  mosq->threaded = mosq_ts_self;
@@ -57,7 +57,7 @@ int mosquitto_loop_start(struct mosquitto *mosq)
 
 int mosquitto_loop_stop(struct mosquitto *mosq, bool force)
 {
-#if defined(WITH_THREADING) && defined(HAVE_PTHREAD_CANCEL)
+#if defined(WITH_THREADING)
 # ifndef WITH_BROKER
  char sockpair_data = 0;
 # endif
@@ -76,9 +76,11 @@ int mosquitto_loop_stop(struct mosquitto *mosq, bool force)
 #endif
  }
 
+#ifdef HAVE_PTHREAD_CANCEL
  if(force){
  pthread_cancel(mosq->thread_id);
  }
+#endif
  pthread_join(mosq->thread_id, NULL);
  mosq->thread_id = pthread_self();
  mosq->threaded = mosq_ts_none;