Proposed libverto integration plan

[Greg Hudson]

On Tue, 2011-08-23 at 17:07 -0400, ghudson at MIT.EDU wrote:
> 1. Bundle the libev source in util/k5ev [...]
> 2. Bundle the core libverto source in util/verto [...]
> 3. Add a libverto-k5ev module to the bundled libverto
> 4. If you configure with --with-system-verto [...]
> 5. If you configure with --without-system-verto [...]
> 6. If you don't specify either [...]

There have been a few adjustments to this plan:

* The k5ev sources are built directly into libverto-k5ev, so there's no
need for a separate libk5ev.

* When using the internal verto, we bypass dynamic linking by including
<libverto-k5ev.h> and calling verto_default_k5ev() instead of
verto_default().

The second adjustment is to make it possible for static builds to work
and to work around current issues with the dynamic linking support on
OSX.

Personally, I'm not 100% happy with handling the problem at the calling
layer.  I'd prefer verto_default() to work for the integrated verto as
well as it does for a system verto.  But Sam and Nathaniel preferred
this approach.

If we do decide to handle this inside verto_default(), it would probably
involve a compiler conditional in verto.c to throw out the dynamic
loading code (which would improve portability) and invoke a specific
loop creation function from verto_default().