[CMake] handling global state

[Brad King]

Brandon J. Van Every wrote:
> IIUC, INTERNAL cache state is meant only for the cache in the 
> current directory.  There is a notation in the LOAD_CACHE documentation: 
> "INCLUDE_INTERNALS can be used to provide a list of internal entries to 
> be included. Normally, no internal entries are brought in. Use of this 
> form of the command is strongly discouraged, but it is provided for 
> backward compatibility."

There is one cache for the entire build tree.  See my other response.

LOAD_CACHE is for use only in looking at outside build trees, and is 
really no longer needed at all.  Just ignore it.

-Brad