winmm: Disable system thread if poll() support is missing.

dlls/winmm/time.c

@@ -116,6 +116,7 @@ static inline void link_timer( WINE_TIMERENTRY *timer )
 #define MMSYSTIME_MININTERVAL (1)
 #define MMSYSTIME_MAXINTERVAL (65535)
 
+#ifdef HAVE_POLL
 
 /**************************************************************************
  *           TIME_MMSysTimeCallback
@@ -254,6 +255,15 @@ static void TIME_MMTimeStart(void)
     }
 }
 
+#else  /* HAVE_POLL */
+
+static void TIME_MMTimeStart(void)
+{
+    FIXME( "not starting system thread\n" );
+}
+
+#endif  /* HAVE_POLL */
+
 /**************************************************************************
  * 				TIME_MMTimeStop
  */