Work around placement new breakage by wx/msw/msvcrt.h

Including that header breaks any use of placement new, such as the one
in wx/any.h, so we need to explicitly undefine (and then redefine it
back) "new" to make it compile in case wx/msw/msvcrt.h is included
first.

include/wx/any.h

@@ -205,9 +205,18 @@ public:
     static void SetValue(const T& value,
                          wxAnyValueBuffer& buf)
     {
-        // Use placement new
+        // Use placement new, taking care to avoid running into problems with
+        // "new" redefinition in wx/msw/msvcrt.h.
+#ifdef WXDEBUG_NEW
+    #undef new
+#endif
+
         void* const place = buf.m_buffer;
         ::new(place) T(value);
+
+#ifdef WXDEBUG_NEW
+    #define new WXDEBUG_NEW
+#endif
     }
 
     static const T& GetValue(const wxAnyValueBuffer& buf)