[CMake] Memory cleanup of variables

[Naram Qashat]

I have a CMake project that I have been testing with various verisons of CMake 
2.4.x and 2.6.x to make sure it works as far back as 2.4.0, due to not knowing 
what version of CMake our users will be using since a lot of them use shells. 
In some instances, I have to read lines from a file using a specific regular 
expression.  With CMake 2.6.x, this works fine using the file(STRINGS) command. 
  With CMake 2.4.x, though (I haven't checked what versions specifically), after 
reading in a lot of files, I notice that a "memory exhausted" error comes up. 
I'm wondering when CMake cleans up the memory it uses, and if there is a way 
around this problem.  I would prefer not to force our uses to use CMake 2.6.x if 
their shell provider won't provide them something newer.

Thanks,
Naram Qashat