klee problems configuring

Hello,

I am trying to get klee to compile on debian 7.8 amd64 system.

I have successfully installed llvm release build from within the
llvm-top folder, but when I try to configure klee, it keeps saying it
cannot autodetect the llvm build mode even though I pass the
--with-llvm-build-mode=Release switch.

Any thoughtswould be appreciated.

Tia,
Donald