d3dx9_26: Add custom ID3DXEffect interface.

[Henri Verbeet]

2011/9/29 Rico Schüller <kgbricola at web.de>:
> 4. Implement each version on it's own, so each dll would get it's own code
> base. This way all differences could be handled correctly.
>
> Thus the only version which would really work 100% is #4, but due to not
> knowing the small differences and the huge amount of work which is needed,
> #4 seems to be practically out of scope. We have to switch to that later if
> we see no way to solve the version differences.
It's probably not worth it if it's just a few functions and a couple
of interfaces, but you could also create a static library like e.g.
libwpp.