[CMake] CMake add_subdirectory and recompiling

[André Caron]

I've recently been surprised by the behavior of CMake when modifying
"CMakeLists.txt" files pointed to by "add_subdirectory()" directives.
I've asked the question on StackOverflow[1] and have gotten no clean
answer.  If anyone is interested, there is a small bounty (50 points)
on the question expiring in a few hours.

The question is tad bit lengthy, so I won't duplicate here.  Any reply
on either the mailing list or to the linked StackOverflow question is
appreciated.

Thanks!
André

[1]: http://stackoverflow.com/questions/8479929/cmake-add-subdirectory-and-recompiling