review request for devel/libavl update

[Rodrigo OSORIO]

Hi,

I just finish the version update for devel/libavl,
a library to manipulate avl trees. In the latest
version, the authors switch from a dynamic linked
library to a source code version you can include
in your project and compile with.

This changes a lot the nature of the port and its
location.

At this point I need some review and feedback.

https://reviews.freebsd.org/D3677

Thanks for your time
- rodrigo