we can use the virtual BINARY_TAGx86_64-centos7-gcc9+py3-opt to implicitly pick up LCG_XYpython3 instead of the declared LCG_XY
the CMake variable LCG_LAYER can be used to use the LCG release LCG_XY_${LCG_LAYER} instead of the plain LCG_XY
the option LCG_USE_GENERATORS can be used to fill the CMAKE_PREFIX_PATH with the packages in LCG_generators_<platform>.txt in addition to those in LCG_externals_<platform>.txt
Note that these changes are only relevant to LHCb, as ATLAS does not use the CMake toolchain to configure the build.
Marco Clemencic authored