multi: work correctly in case of no sockets

Fix WinSock version to work correctly in case no sockets
are to be waited on and just the WinSock event is being
monitored for wakeup functionality.

Author: mback2k

lib/multi.c

@@ -1247,13 +1247,19 @@ static CURLMcode Curl_multi_wait(struct Curl_multi *multi,
 #endif
 #endif
 
+#if defined(ENABLE_WAKEUP) && defined(USE_WINSOCK)
+  if(nfds || use_wakeup) {
+#else
   if(nfds) {
+#endif
     int pollrc;
 #ifdef USE_WINSOCK
-    pollrc = Curl_poll(ufds, nfds, 0); /* just pre-check with WinSock */
-    if(pollrc <= 0) { /* now wait... if not ready during the pre-check above */
-     WSAWaitForMultipleEvents(1, &multi->wsa_event, FALSE, timeout_ms, FALSE);
-    }
+    if(nfds)
+      pollrc = Curl_poll(ufds, nfds, 0); /* just pre-check with WinSock */
+    else
+      pollrc = 0;
+    if(pollrc <= 0) /* now wait... if not ready during the pre-check above */
+      WSAWaitForMultipleEvents(1, &multi->wsa_event, FALSE, timeout_ms, FALSE);
 #else
     pollrc = Curl_poll(ufds, nfds, timeout_ms); /* wait... */
 #endif
@@ -1354,10 +1360,11 @@ static CURLMcode Curl_multi_wait(struct Curl_multi *multi,
     free(ufds);
   if(ret)
     *ret = retcode;
-  if(!extrawait || nfds)
-    /* if any socket was checked */
-    ;
-  else {
+#if defined(ENABLE_WAKEUP) && defined(USE_WINSOCK)
+  if(extrawait && !nfds && !use_wakeup) {
+#else
+  if(extrawait && !nfds) {
+#endif
     long sleep_ms = 0;
 
     /* Avoid busy-looping when there's nothing particular to wait for */