Simage is a library for image, movie and sound I/O. It's used primarily by the Coin3d library.
Created attachment 50907 [details]
You must not comment SLOT; you should pass option directly to econf instead of using myconf, and you should be sure that the useflags aren't auto-tested. As you don't pass any option for the useflags to econf, I think it will autocheck and adds dependencies automagically which is really bad.
Please also note that oggvorbis useflag is deprecated and is now called just vorbis.