Do export wxMSWOwnerDrawnButton from DLL in wxMSW.

This class shouldn't need to be exported but not doing it breaks builds using
LTCG with Intel compiler, so do export it to avoid this problem.

Closes #16237.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76485 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/ownerdrawnbutton.h

@@ -17,11 +17,11 @@
 // This class contains the type-independent part of wxMSWOwnerDrawnButton and
 // is implemented in src/msw/control.cpp.
 //
-// Notice that it is intentionally not DLL-exported, it is internal
-// implementation detail only. However MSVS generates a warning C4275 when
-// deriving from the non-exported classes, so it needs to be explicitly
-// disabled when deriving from this one.
-class wxMSWOwnerDrawnButtonBase
+// Notice that this class is internal implementation detail only and is
+// intentionally not documented. Ideally it wouldn't be even exported from the
+// DLL but this somehow breaks building of applications using wxWidgets with
+// Intel compiler using LTCG, so we do export it.
+class WXDLLIMPEXP_CORE wxMSWOwnerDrawnButtonBase
 {
 protected:
     // Ctor takes the back pointer to the real window, must be non-NULL.
@@ -91,8 +91,9 @@ private:
 // This class uses a weak version of CRTP, i.e. it's a template class taking
 // the base class that the class deriving from it would normally derive from.
 template <class T>
-class wxMSWOwnerDrawnButton : public T,
-                              private wxMSWOwnerDrawnButtonBase
+class WXDLLIMPEXP_CORE wxMSWOwnerDrawnButton
+    : public T,
+      private wxMSWOwnerDrawnButtonBase
 {
 private:
     typedef T Base;