If you look at Tim's pull request, you will see that Direct2D is enabled for building C::B, so I guess the answer is Yes.
It's only one issue and will help building wxWidgets as it will mean you do not have to manually change the define, BUT the standard MSYS2 wxWidget 3.1.5 source did not include private wxwidget directories that C::B requires to build and as such I will wait for it to pop up in my pacman updates.