Remove compile-time checks for always defined WM_XXX in wxMSW

The symbols in question are present at least since XP, and most of them since
Windows 2000, so remove preprocessor checks for them, they shouldn't be needed
when any remotely current compiler/SDK.

src/msw/anybutton.cpp

@@ -90,10 +90,6 @@ using namespace wxMSWImpl;
     #endif
 #endif // wxUSE_UXTHEME
 
-#ifndef WM_THEMECHANGED
-    #define WM_THEMECHANGED     0x031A
-#endif
-
 #ifndef ODS_NOACCEL
     #define ODS_NOACCEL         0x0100
 #endif

src/msw/evtloop.cpp

@@ -328,9 +328,7 @@ void wxGUIEventLoop::DoYieldFor(long eventsToProcess)
             case WM_SYSKEYUP:
             case WM_SYSCHAR:
             case WM_SYSDEADCHAR:
-#ifdef WM_UNICHAR
             case WM_UNICHAR:
-#endif
             case WM_HOTKEY:
             case WM_IME_STARTCOMPOSITION:
             case WM_IME_ENDCOMPOSITION:
@@ -349,9 +347,7 @@ void wxGUIEventLoop::DoYieldFor(long eventsToProcess)
 
             case WM_MOUSEHOVER:
             case WM_MOUSELEAVE:
-#ifdef WM_NCMOUSELEAVE
             case WM_NCMOUSELEAVE:
-#endif
 
             case WM_CUT:
             case WM_COPY:

src/msw/listctrl.cpp

@@ -3157,12 +3157,10 @@ wxListCtrl::MSWWindowProc(WXUINT nMsg, WXWPARAM wParam, WXLPARAM lParam)
 {
     switch ( nMsg )
     {
-#ifdef WM_PRINT
         case WM_PRINT:
             // we should bypass our own WM_PRINT handling as we don't handle
             // PRF_CHILDREN flag, so leave it to the native control itself
             return MSWDefWindowProc(nMsg, wParam, lParam);
-#endif // WM_PRINT
 
         case WM_CONTEXTMENU:
             // because this message is propagated upwards the child-parent

src/msw/spinctrl.cpp

@@ -101,12 +101,10 @@ wxBuddyTextWndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
         case WM_DEADCHAR:
         case WM_KEYUP:
         case WM_KEYDOWN:
-#ifdef WM_HELP
         // we need to forward WM_HELP too to ensure that the context help
         // associated with wxSpinCtrl is shown when the text control part of it
         // is clicked with the "?" cursor
         case WM_HELP:
-#endif
             {
                 WXLRESULT result;
                 if ( spin->MSWHandleMessage(&result, message, wParam, lParam) )

src/msw/window.cpp

@@ -71,9 +71,6 @@
     #include "wx/access.h"
     #include <ole2.h>
     #include <oleacc.h>
-    #ifndef WM_GETOBJECT
-        #define WM_GETOBJECT 0x003D
-    #endif
     #ifndef OBJID_CLIENT
         #define OBJID_CLIENT 0xFFFFFFFC
     #endif
@@ -3292,7 +3289,6 @@ wxWindowMSW::MSWHandleMessage(WXLRESULT *result,
             }
 #endif
 
-#if defined(WM_HELP)
         case WM_HELP:
             {
                 // by default, WM_HELP is propagated by DefWindowProc() upwards
@@ -3328,7 +3324,6 @@ wxWindowMSW::MSWHandleMessage(WXLRESULT *result,
                 }
             }
             break;
-#endif // WM_HELP
 
         case WM_CONTEXTMENU:
             {