In process of module testing event_groups.c.

Introduce xPortRunning variable into Win32 simulator port layer.
Add port optimised task selection macro for the GCC Win32 port layer (the MSVC version has had one for a while).
Ensure the event list item value does not get modified by code in tasks.c (priority inheritance, or priority change) when it is in use by the event group implementation.

FreeRTOS/Source/include/timers.h

@@ -993,6 +993,9 @@ xTaskHandle xTimerGetTimerDaemonTaskHandle( void );
  * *pxHigherPriorityTaskWoken must be initialised to pdFALSE.  See the
  * example code below.
  *
+ * @return pdPASS is returned if the message was successfully sent to the
+ * timer daemon task, otherwise pdFALSE is returned.
+ *
  * Example usage:
  * @verbatim
  *