share wxEventLoop::IsRunning() implementation between all ports; moved wxEventLoopActivator used by it in wx/evtloop.h instead of duplicating it in 3 different .cpp files (and not using it at all in 3 other ones)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@36842 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/x11/evtloop.cpp

@@ -357,8 +357,7 @@ int wxEventLoop::Run()
 
     m_impl = new wxEventLoopImpl;
 
-    wxEventLoop *oldLoop = ms_activeLoop;
-    ms_activeLoop = this;
+    wxEventLoopActivator activate(this);
 
     m_impl->m_keepGoing = TRUE;
     while ( m_impl->m_keepGoing )
@@ -400,8 +399,6 @@ int wxEventLoop::Run()
     delete m_impl;
     m_impl = NULL;
 
-    ms_activeLoop = oldLoop;
-
     return exitcode;
 }