[CMake] XCode automatic dependencies

[Jeroen Dierckx]

Hi,

We are in the progress of converting our build system(s) to cmake, and
we are working on the following platforms:
- Windows (VS2008)
- Linux (KDevelop)
- Mac OSX Snow Leopard (XCode)
- iPhone (through XCode)

Everything works very good, and I am glad that we took the dive. In
XCode however, dependencies on other cmake-generated targets aren't
setup automatically. The CMake book and documentation states that it
is enough to use target_link_libraries, and cmake should detect all
internal dependencies automatically. This works perfectly in our
generated Visual Studio files, but it doesn't work on XCode.

When I explicitly use add_dependency with the same targets, everything
is setup correctly, also in XCode.

Greetings,
JeDi