[CMake] add_custom_target: always built during "make" and "make install"

[Tyler Roscoe]

On Mon, Nov 02, 2009 at 11:28:08PM +0800, Romain CHANU wrote:
> 1. If there is a restriction / condition regarding the "out-of-date"
> behavior, it might be good to update the documentation.

Agreed, but I don't understand the behavior so I can't help with that.

> 3. I am not 100% sure also... Anyone to give us an advice on that matter??

Why don't you experiment with an explicit list and see if the behavior
changes? Science to the rescue!

tyler