Chris Tapp wrote:

I need to include libSDL (and related libs) in to my build, but I
can't see the recipes in Yocto (other than -nativesdk).

Can I just copy the appropriate OE recipes in to Yocto?

In poky we have meta/recipes-graphics/libsdl/libsdl-nativesdk_1.2.11.bb (looks it's not acutally used at present?)

I think you can do the following to add libsdl into target image:
1) change the file name to libsdl_1.2.11.bb;
2) add BBCLASSEXTEND = "nativesdk" into the file;
3) remove nativesdk from the "inherit" of the file;
4) add libsdl into a proper RDEPENDS, e.g., SDK-EXTRAS.

Thanks,
-- Dexuan