[CMake] find_package and INTERFACE targets in 3.0

[Walter Gray]

Hi list!

I'm a big fan of the new INTERFACE targets & target usage requirements, 
but none of the provided Find<package>.cmake files seem to take 
advantage of the new paradigm.  Checking the wiki, the old 
Find<package>.cmake seem to be deprecated, with most of the information 
on authoring new packages assuming that you are the developer of the 
module, not the consumer. What is the recommended way to deal with 
packages that don't provide these config files? I'll happily write my 
own Find<package>.cmake files, however that approach seems deprecated 
and I haven't found any good examples of find modules that define IMPORT 
or INTERFACE targets instead of the older method of setting a bunch of 
<package>_xxx variables.

-Walter