ROOTSYS in root6

[yszhang95]

I want to integrate ROOT with external packages. Packages can be found ​https://gitlab.cern.ch/cburgard/RooFitExtensions I have the following errors

  By not providing "FindROOT.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "ROOT", but
  CMake did not find one.

  Could not find a package configuration file provided by "ROOT" with any of
  the following names:

    ROOTConfig.cmake
    root-config.cmake

  Add the installation prefix of "ROOT" to CMAKE_PREFIX_PATH or set
  "ROOT_DIR" to a directory containing one of the above files.  If "ROOT"
  provides a separate development package or SDK, be sure it has been
  installed.

I checked the link ​https://root-forum.cern.ch/t/integrating-root-using-cmake/20195/3 I suppose the errors are from system cannot find ROOTSYS. I searched a bit and did not find any solutions in MacPorts. Could the maintainer have a look?

Best regards