[compiz] glu dependency

[Danny Baumann]

Hi,

> The following commit seems to have added a dependency on glu but does
> no checks to see if it is actually available:
> 
> commit fa5bf5754d8a2e47d659a3abe5cb59a7b0e304d7
> Author: David Reveman <davidr at novell.com>
> Date:   Tue Jan 16 06:07:39 2007 +0100
> 
>     Project vertices and only update minimum required destination texture
>     region. Some more optimizations should be done here but the current
>     changes should still give a major performance improvement.
> 
> 
> My autofoo is very much lacking so I'm not sure how to add such a check.

Problem here is that GLU does not provide a pkg-config .pc file which is
needed to check a libraries availability through configure.ac. libjpeg
has the same problem, BTW.
We could add a check for the header file presence, but I am not sure if
this is a proper solution or is somewhat kludgy.

Regards,

Danny