Cmake cant find vmc to build GEANT3

Dear experts,
currently I have some trouble building GEANT3 on my Mac (10.15.5).
It seems like cmake cannont find the dependency VMC needed by GEANT3:

CMake Warning (dev) at cmake/Geant3RequiredPackages.cmake:16 (find_package):
  Policy CMP0074 is not set: find_package uses <PackageName>_ROOT variables.
  Run "cmake --help-policy CMP0074" for policy details.  Use the cmake_policy
  command to set the policy and suppress this warning.

  Environment variable ROOT_ROOT is set to:


  For compatibility, CMake is ignoring the variable.
Call Stack (most recent call first):
  CMakeLists.txt:53 (include)
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Error at cmake/Geant3RequiredPackages.cmake:29 (find_package):
  Could not find a package configuration file provided by "VMC" with any of
  the following names:


  Add the installation prefix of "VMC" to CMAKE_PREFIX_PATH or set "VMC_DIR"
  to a directory containing one of the above files.  If "VMC" provides a
  separate development package or SDK, be sure it has been installed.
Call Stack (most recent call first):
  CMakeLists.txt:53 (include)

-- Configuring incomplete, errors occurred!

As “VMC” apparently is a part of root, my first guess from this warning was that maybe here cmake is not using the ROOT version installed with aliBuild but instead the one from my system (where maybe vmc is not included?).

It might also be worth mentioning that in order to get the aliBuild ROOT version to compile, I had to add the flag -Dbuiltin_glew=ON in of alidist .
This is because of an issue with mac and the current cmake version reported in the root forum:

and discussed in this JIRA ticket:
Newer root versions would also give a warning about this:

With this manual enabeling of the builtin glew, root compiles just fine, but I am not sure if this somehow as a side-effect could result in vmc not beeing included in the ROOT build.

I would appreciate any help or hints to solve this problem.


Just in case someone else encounters a similar prolbem:
This was indeed a related to a mixup with my systems root installation.
After sourcing the ‘’ script belonging to the ROOT version installed by aliBuild, cmake stopped complaining and GEANT3 was compiled without errors.