Don't check if WM_XBUTTONxxx are defined in wxMSW code

This is not necessary any longer, we don't support Windows CE any more and
these constants are available since Windows 2000 in the desktop Windows SDKs.

src/msw/window.cpp

@@ -141,12 +141,6 @@
     #define HAVE_TRACKMOUSEEVENT
 #endif // everything needed for TrackMouseEvent()
 
-// not all compilers/platforms have X button related declarations (notably
-// Windows CE doesn't, and probably some old SDKs don't neither)
-#ifdef WM_XBUTTONDOWN
-    #define wxHAS_XBUTTON
-#endif
-
 #ifndef MAPVK_VK_TO_CHAR
     #define MAPVK_VK_TO_CHAR 2
 #endif
@@ -2915,11 +2909,9 @@ wxWindowMSW::MSWHandleMessage(WXLRESULT *result,
         case WM_MBUTTONDOWN:
         case WM_MBUTTONUP:
         case WM_MBUTTONDBLCLK:
-#ifdef wxHAS_XBUTTON
         case WM_XBUTTONDOWN:
         case WM_XBUTTONUP:
         case WM_XBUTTONDBLCLK:
-#endif // wxHAS_XBUTTON
             {
                 int x = GET_X_LPARAM(lParam),
                     y = GET_Y_LPARAM(lParam);
@@ -5311,10 +5303,8 @@ void wxWindowMSW::InitMouseEvent(wxMouseEvent& event,
     event.m_leftDown = (flags & MK_LBUTTON) != 0;
     event.m_middleDown = (flags & MK_MBUTTON) != 0;
     event.m_rightDown = (flags & MK_RBUTTON) != 0;
-#ifdef wxHAS_XBUTTON
     event.m_aux1Down = (flags & MK_XBUTTON1) != 0;
     event.m_aux2Down = (flags & MK_XBUTTON2) != 0;
-#endif // wxHAS_XBUTTON
     event.m_altDown = ::wxIsAltDown();
 
     event.SetTimestamp(::GetMessageTime());
@@ -5353,7 +5343,6 @@ bool wxWindowMSW::HandleMouseEvent(WXUINT msg, int x, int y, WXUINT flags)
         wxEVT_AUX2_DCLICK
     };
 
-#ifdef wxHAS_XBUTTON
     // the same messages are used for both auxiliary mouse buttons so we need
     // to adjust the index manually
     switch ( msg )
@@ -5364,7 +5353,6 @@ bool wxWindowMSW::HandleMouseEvent(WXUINT msg, int x, int y, WXUINT flags)
             if ( flags & MK_XBUTTON2 )
                 msg += wxEVT_AUX2_DOWN - wxEVT_AUX1_DOWN;
     }
-#endif // wxHAS_XBUTTON
 
     wxMouseEvent event(eventsMouse[msg - WM_MOUSEMOVE]);
     InitMouseEvent(event, x, y, flags);
@@ -6430,10 +6418,8 @@ wxMouseState wxGetMouseState()
     ms.SetLeftDown(wxIsKeyDown(VK_LBUTTON));
     ms.SetMiddleDown(wxIsKeyDown(VK_MBUTTON));
     ms.SetRightDown(wxIsKeyDown(VK_RBUTTON));
-#ifdef wxHAS_XBUTTON
     ms.SetAux1Down(wxIsKeyDown(VK_XBUTTON1));
     ms.SetAux2Down(wxIsKeyDown(VK_XBUTTON2));
-#endif // wxHAS_XBUTTON
 
     ms.SetControlDown(wxIsCtrlDown ());
     ms.SetShiftDown  (wxIsShiftDown());