> Why not generate the headers from the modules, then users don't have to worry about them.

That's the approach I took; this brings the limitation that the only thing that can be publicly exported from a module are things that are compatible with C code.

It also makes modules useless - what use would a module be if the interface is fully specified in a header anyway? Just read the header.

TBH, I'm still in the design phase so I tend to change my idea of what's good and bad quite frequently.