[CMake] Couple of library/link questions

[Oliver kfsone Smith]

Jean-Christophe Fillion-Robin said the following on 3/20/2012 5:54 PM:
> Hi Olivier,
>
> Assuming you have not set the flag, BUILD_SHARED_LIBS [1] set to TRUE, 
> I will  consider you are building static libraries. If this last 
> statement is valid, it seems your approach is the right one.
Ah, I actually expose it as a variable so that the build process can 
decide whether they should be shared or not :)
>
> I would also recommend you to read the following entry: 
> http://vtk.org/Wiki/CMake_FAQ#Does_CMake_support_.22convenience.22_libraries.3F
I did actually look to the FAQ, but I didn't make the connection, 
although what I was actually trying to do was make the 3rd library 
(libevent) an archive of all the .obj files produced during the 
compilation of the first two libraries, rather than an empty stub :) I 
realize that this case is slightly trivial, but that's just my working 
point in the conversion; there are actually several other 
module-libraries which it compiles both into the full libevent lib and 
as stand-alone modules to allow end-users to be choosy about which 
components they require.

- Oliver