[CMake] Removing unused variables from the cache

[Sylvain Benner]

Hello,

I don't know if this is possible but you can set your variable to an empty 
string.

SET( SOME_OPTION "")

Sylvain

> Hi,
>
> Is it possible to remove variables from the cache ? For example:
>
> OPTION( BUILD_X "Descr" OFF )
>
> IF ( BUILD_X )
>    SET( SOME_OPTION "Hello world" CACHE)
> ELSEIF (BUILD_X)
>    UNSET( SOME_OPTION )
> ENDIF ( BUILD_X )
>
> Peter