[CMake] Unnecessary rebuilds on windows

[Kevin Burge]

I'm having a problem where I make some change to one of the 
CMakeLists.txt file in the root of a large tree of projects and on 
windows, when the configure/generate stage is done, it wipes out all the 
stamp files and directories created by add_custom_command, and basically 
rebuilds everything.  My build takes 2+ hours to complete, so it's 
making testing very time consuming.  Is there a way to audit what the 
configure/generate stage is doing when I run nmake so I can tell why it 
thinks all of my targets are out of date?

This is 2.8.0 rc 3.

Thanks,
Kevin