Compilation Failure CONFIGURATION_ROOT_DIR

I am trying to build Salome’s kernel for NixOS, in setting this up I receive the following error:

CMake Error at CMakeLists.txt:36 (MESSAGE):
  We absolutely need the Salome CMake configuration files, please define
  CONFIGURATION_ROOT_DIR !

Reading CMakeLists.txt gives no useful additional information. The README also has no information on the definition of this variable. The SALOME cmake docs are also not helpful.

If anyone could please clarify how to resolve this, I would appreciate it. Build log attached.
build.log (3.6 KB)

You need a repository called CONFIGURATION and then to define CONFIGURATION_ROOT_DIR with its path.