[CMake] Can't force compiler to g++/gcc when compiling PV

[Peter J. Bismuti]

I'm following this ste:

    env CXX=/your/C++/compiler CC=/your/c/compiler ccmake . 

And in ccmake I'm setting the compiler path, but after I configure, it keeps 
overwriting it with different compilers.  How can I force ccmake to take the 
compilers that I want?  

Thanks in advnace