I got it working, looks very nice , but it is just a hack. I have to figure out how to do it the right way if I'm ever going to lobby(?) to get it included in the main branch (I've never contributed anything to an open source project before). Which is important, for all the frontends that seem to like to compile all of mame into the frontend itself.
The problem with glsl is that no one cares about it on windows. So no support (compiling or otherwise) (still can't even get onto the msg board), few binaries, no frontends (except maybe, at some point, CiroConsentino's).
I guess I was a little bit irritated that this extremely (to my mind, over-)complicated shader, was promoted to mainline mame, as if it was the be all, end all of shaders, without the very, very basic facility for running one's own shaders. Though it is his project, he did the work, so I can hardly be mad at him.