[U-Boot] exports.h and the GPL

Hi,

As far as i know applications can use functions defined in exports.h without being licensed under the GPL.

Who is responsible to define which functions are exported? Are the currently exported functions the only ones available to closed source applications or is it possible to add further ones which are needed.

Functions may need arguments which are pointers to some structures. These structures are likely be defined in some GPL'ed header file and must not be used, i guess? So the exported functions must only use integral data types, opaque pointers and structures which are not defined in a GPL'ed header file.

I'm aware of the fact that I won't get any legal advice, I'm just asking for your opinions.