Add support for special LCG versions
- we can use the virtual
BINARY_TAGx86_64-centos7-gcc9+py3-optto implicitly pick upLCG_XYpython3instead of the declaredLCG_XY - the CMake variable
LCG_LAYERcan be used to use the LCG releaseLCG_XY_${LCG_LAYER}instead of the plainLCG_XY - the option
LCG_USE_GENERATORScan be used to fill theCMAKE_PREFIX_PATHwith the packages inLCG_generators_<platform>.txtin addition to those inLCG_externals_<platform>.txt
Note that these changes are only relevant to LHCb, as ATLAS does not use the CMake toolchain to configure the build.
Edited by Marco Clemencic