[CMake] using find_library with a ExternalProject

[Bill Hoffman]

On 10/22/2012 12:34 PM, Ian Monroe wrote:
> So what was the target use-case for ExternalProject? From the name it
> sounds like it was meant exactly for making your non-external project
> (aka your project) be able to pull in dependencies from external
> projects.
The target use case was to create a simple way to build large 
complicated projects that depend on lots of third party software.
http://www.kitware.com/media/html/BuildingExternalProjectsWithCMake2.8.html

>
> To make the project itself an external project gives up a lot of
> flexibility in cmake configuration. And would just plan mess up my
> source tree.:)
Yes, and no.  It still creates a direct cmake project for your project. 
  You can use the external project to create a "super build" for your 
project.  This could be used to bootstrap and setup a project with all 
of its depends.  Then you can work directly in the project after the 
initial configuration.

Because the source in most times does not even exist, it would be 
impossible for the find_* stuff to find anything.  This is just how it 
works.

-Bill