[CMake] Implicity CMAKE_CURRENT_BINARY_DIR include_directories

[Brad King]

Denis Scherbakov wrote:
>> On Monday 11 May 2009, Denis Scherbakov wrote:
>>> CMAKE_LINK_DEPENDS_DEBUG_MODE is also not documented.
>> Is this one an official public variable or may it go away
>> again ?
> 
> If you ask me - I don't know, I am not a CMake developer.
> But there is a lot functionality built around this variable in one of CMake
> source files. So I think it is for a long time there.

It's purposely undocumented.  I used that variable while debugging
the link dependencies computation code.  Some day it might help diagnose
a bug report for some user so I left it in.  It's output format is
totally unspecified.

-Brad