[CMake] Overwriting variables in cache.

[Benoit Thomas]

Hi,

I am trying to overwrite some variables in the cache (without editing 
the cache); it works well for variables like CMAKE_CXX_FLAGS, but I 
cannot overwirte the CMAKE_CONFIGURATION_TYPES variable. Is there a way 
to do this without having to edit the cache ? (or modifying it the first 
time the cache is build, that would be correct also).

(Sorry if this sound confusing, I just started using cmake)

Thank you,
Ben.