[Sheepdog] [PATCH] configure: add urcu into configure

[Christoph Hellwig]

On Tue, May 08, 2012 at 11:31:53PM +0800, Liu Yuan wrote:
> Yes, the latest urcu code provide a .pc file and it seems that the atomic header structure get
> changed over time. Let's stick to the latest new structure and would better write a script to auto
> download, compile and install it or point people to where he can finds the latest version to compile.

Not being able to use commonly packaged versions of dependencies is
a major pain for anyone using a package.  So far it seems like the only
problem is the configure script.  Unless we really need newer features
inside the core code I'd really prefer allowing older versions.  I'll
volunteer to add configure support for it.