Temp bashed mac-ogl.mk in Makefile.

- This branch doesn't have mechs to exclude .mm projects on non .mm targets.
Third party builds now use CMAKE --build, rather than a cooked command.
-pthread is correctly passed to gcc-compatible builds again.
Views no longer have a created but not open state.

- Supporting 2-phase construction (create, then open) is bad enough on
xlib/glx. It's a nightmare xplat. It has been disabled.
- In the future, it is likely that we'll move to having only one video object
at all, similar to sdl.