We need a non-template ctor to make the code initializing wxWeakRef with literal NULL to compile. Closes #11916. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63934 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@51231 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@51187 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775