[CMake] Couple of library/link questions

[Oliver kfsone Smith]

Andreas Pakulat said the following on 3/20/2012 5:21 PM:
>> - The makefiles I'm basing this on build libevent_core.lib,
>> libevent_extras.lib and then libevent.lib which is basically the two
>> previous libraries merged.
>>
>> I wanted to do:
>>
>> ADD_LIBRARY(libevent_core ${CoreSrcFiles})
>> ADD_LIBRARY(libevent_extras ${ExtraSrcFiles})
>> ADD_LIBRARY(libevent)
>> TARGET_LINK_LIBRARIES(libevent libevent_core libevent_extras)
>>
>> but this generates a warning/error,  listing the two libraries in
> Whats the error? It should just work.
I mis-spoke; it gives a /warning/ for the ADD_LIBRARY(libevent) with no 
source files, warning that it is usually an error in the CMakeLists.txt 
file.

- Oliver