Split wxWakeUpPipe class in MT-unsafe and MT-safe parts.

This class can also be useful when it's used in the main thread only, so
leave the lock-less part of the code in wxWakeUpPipe and derive a separate
wxWakeUpPipeMT from it for the use in wxConsoleEventLoop where it can be used
by multiple threads.

See #10258.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74339 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/unix/evtloop.h

@@ -19,7 +19,7 @@
 
 class wxFDIODispatcher;
 class wxUnixEventLoopSource;
-class wxWakeUpPipe;
+class wxWakeUpPipeMT;
 
 class WXDLLIMPEXP_BASE wxConsoleEventLoop
 #ifdef __WXOSX__
@@ -52,7 +52,7 @@ protected:
 private:
     // pipe used for wake up messages: when a child thread wants to wake up
     // the event loop in the main thread it writes to this pipe
-    wxWakeUpPipe *m_wakeupPipe;
+    wxWakeUpPipeMT *m_wakeupPipe;
 
     // either wxSelectDispatcher or wxEpollDispatcher
     wxFDIODispatcher *m_dispatcher;