[CMake] acyclic subdirectory builds

[Amitha Perera]

Bätge wrote:
 >  ADD_DEPENDENCIES( exea liba )
 >  ADD_DEPENDENCIES( exeb liba )

That should be TARGET_LINK_LIBRARIES.

Egon: as Stephan says, you want to avoid this include() stuff.  That is 
only useful some complicated situations.  What you want is probably 
something like this: (I added a libb for fun.)

/liba/CMakeLists.txt:
   ...
   add_library( liba ... )
   ...

/libb/CMakeLists.txt
   ...
   add_library( libb ... )
   ...

/exea/CMakeLists.txt
   ...
   add_executable( exea )
   target_link_libraries( exea liba libb )
   ...

/exeb/CMakeLists.txt
   ...
   add_executable( exeb )
   target_link_libraries( exeb liba libb )
   ...

/CMakeLists.txt
   PROJECT( proj )
   add_subdirectory( liba )
   add_subdirectory( exea )
   add_subdirectory( exeb )


(You may be able to to the last step from a proj subdirectory, as you 
had in your original email, but I can't remember right now if that is a 
2.4.x feature or a 2.6.x feature.)

If you move to CMake 2.6, you can even create self-standing sub-project 
solutions.  (I think CMake 2.4 doesn't quite do that, but I could be wrong.)

Amitha.