[CMake] Omitted dependencies.

[Óscar Fuentes]

A project named Bar includes other source trees like this:

add_subdirectory(../Foo)

It seems that dependencies on Foo's header files are being ignored. When
a header file in Foo's source tree is modified, C++ files on Bar that
includes that header are not rebuilt.

I'll like to investigate this. What's the file where cmake stores header
file dependencies?

Using 2.6.1 on Linux with Unix makefiles.

-- 
Oscar