[CMake] Tricky question once more

[Denis Scherbakov]

Once more: I have 3 projects.

projectA depends on projectB
projectB depends on SOMEAPP_INCLUDES and SOMEAPP_LIBRARIES
projectC does not depend on anything

I have FindSomeApp script that sets SOMEAPP_FOUND

1. I want to be able to complete cmake configuration, and build projectC, even if projectB
and projectA cannot be built. Currently I get an error "The following variables are used in
this project, but they are set to NOTFOUND."

2. My project is very big, so putting everywhere IF-ENDIF is not an option, I need some
automatic way. I can rewrite ADD_SUBDIRECTORY, though, but how?

3. projectA cannot be built, because it has failed dependencies, I also want to track
somehow projects that depends on projects that have failed dependencies.

Comeon, people! I don't believe that everybody has one toplevel executable that you want
to get without small subprojects that depend on smaller set of libs.

Denis