The biggest pain I have found in trying to make this work (I did my initial work on 386BSD 0.0 and 0.1 on a Sun hosted environment because I couldn't get a machine up until the kernel had been patched in at least 3 places) was the compilation tools.

GCC's idea of a hosted cross-compilation environment is orthoganal to the idea of the compiler being a system component and to the cross-compilation environment being a system instead of an application.

The clearest artifact of this is the way it handles include files and the compiler having an expectation of the cross-compilation and compilation environments having the same install tree.

Anything that gets done will eventaully have to reflect a special status fo the tools.