solver=installation p. 1: including directly vs. delivering external headers

Hi all,

with gbuild expanding (thanks to David tirelessly working on that :-))
things are more under control and we don't need to use solver for
other modules that much.
In theory, (later,) in solver could be only stuff needed for
make_installer.pl I think. Or better the solver can be installation.

I think the plan for headers is to avoid delivering them, move and use
only one include path, mainly because of Windows.
And this is waiting for re-licensing. But there are other things to do.

What about external headers ?
We could move also x11_extensions/, Mesa/, ... but maybe we don't want
to mix them ?
And we can't move headers from tarball as vigra.
So we need either deliver them somewhere* or add include path for them.
I think include path could be fine since they are not used that much ?

*if we deliver to solver, then there should be another directory for
installation, so delivering to workdir could be better.

I think the result is going to be cool, esp. for Windows without
symlinks but no idea about the time, at worse in a year I hope.

Thanks for listening and/or ideas,
Matus