Added wxThread::OnKill() and OnDelete() callbacks.

Call OnXXX() from wxThread::Kill() and Delete() respectively to allow the
thread being terminated perform some cleanup.

Closes #9046.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65882 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/unix/threadpsx.cpp

@@ -1453,6 +1453,8 @@ wxThreadError wxThread::Delete(ExitCode *rc)
 
     m_critsect.Leave();
 
+    OnDelete();
+
     switch ( state )
     {
         case STATE_NEW:
@@ -1501,6 +1503,8 @@ wxThreadError wxThread::Kill()
     wxCHECK_MSG( This() != this, wxTHREAD_MISC_ERROR,
                  wxT("a thread can't kill itself") );
 
+    OnKill();
+
     switch ( m_internal->GetState() )
     {
         case STATE_NEW: