add_dependencies: document limitations with custom targets in Visual Studio
When calling 'add_dependencies' with two targets, neither of which are marked 'ALL', a generated VS2015 and VS2013 solution will add the dependency to the configurations build list; so that when you do a 'build solution' it runs that target.
It does NOT add it as a dependency to the ALL_BUILD target, just to the solutions default build targets.
In the attached example, you can see this behavior -- targetA gets built on a build solution. If you comment out the add_dependencies line, targetA is no longer added to the solutions default build targets.
This seems like it can't be the expected behavior of add_dependencies in this case, but maybe I'm missing something about why / how it needs to do this?