Fix wxMSW build with wxUSE_DEFERRED_SIZING==0

Don't define BeginRepositioningChildren() and EndRepositioningChildren() at
all in this case instead of defining them as "do nothing" functions because
BeginRepositioningChildren() still needs to return a bool, so the old code
didn't compile and we would need to add another "#else" to fix this -- instead
make it simpler by just not compiling at all in this case.

src/msw/window.cpp

@@ -5034,9 +5034,10 @@ bool wxWindowMSW::HandleExitSizeMove()
     return HandleWindowEvent(event);
 }
 
+#if wxUSE_DEFERRED_SIZING
+
 bool wxWindowMSW::BeginRepositioningChildren()
 {
-#if wxUSE_DEFERRED_SIZING
     int numChildren = 0;
     for ( HWND child = ::GetWindow(GetHwndOf(this), GW_CHILD);
           child;
@@ -5062,12 +5063,10 @@ bool wxWindowMSW::BeginRepositioningChildren()
 
     // Return true to indicate that EndDeferWindowPos() should be called.
     return true;
-#endif // wxUSE_DEFERRED_SIZING
 }
 
 void wxWindowMSW::EndRepositioningChildren()
 {
-#if wxUSE_DEFERRED_SIZING
     wxASSERT_MSG( m_hDWP, wxS("Shouldn't be called") );
 
     // reset m_hDWP to NULL so that child windows don't try to use our
@@ -5091,9 +5090,10 @@ void wxWindowMSW::EndRepositioningChildren()
         wxWindowMSW * const child = node->GetData();
         child->MSWEndDeferWindowPos();
     }
-#endif // wxUSE_DEFERRED_SIZING
 }
 
+#endif // wxUSE_DEFERRED_SIZING
+
 bool wxWindowMSW::HandleSize(int WXUNUSED(w), int WXUNUSED(h), WXUINT wParam)
 {
     // when we resize this window, its children are probably going to be