libhal, udev, and libvolume_id - licensing??

[Gordon Schumacher]

I am trying to decipher the licensing for libhal and libvolume_id, and
so far I'm just getting confused...

As far as I can tell, libvolume_id is part of the udev package. 
Everything I see indicates that udev is GPLv2... except Gentoo:
http://gentoo-portage.com/dev-libs/libvolume_id

If I download their package, the source files say GPLv2, so I'm assuming
they're wrong.  Okay, so I can safely assume for the moment that I am
not allowed to link a non-GPL program against libvolume_id.

So next is libhal... it lists udev as a dependency, so that makes it
GPLv2 as well.  But wait...

HAL is licensed to you under your choice of the Academic Free
License version 2.1, or the GNU General Public License version 2.
Both licenses are included here. Some individual source code files 
and/or binaries may be under the GPL only or under the LGPG.

Each source code file is marked with the proper copyright information.


Ahhh... help!  If hal is including GPLed source, how can it be
dual-licensed??  My understanding is that you couldn't "un-GPL"
something... and further, the FSF explicitly listst the AFL is
GPL-incompatible, so now I'm *really* confused.

Hopefully someone can help me sort this out!  I'm trying very hard to
stay in the clear with all the licensing requirements - but right now I
haven't the slightest idea whether it's legitimate for me to use libhal
in a non-GPLed project or not; I would think that being the basic way to
access hardware under Linux, it would be possible to use it in a
non-GPLed application, but now I'm really unsure.