Fix stand-alone compilation of public headers
This is needed to be able to build the headers in stand-alone mode, see lhcb-core/LHCbNightlyConf!984 (merged)
Part of a group: LHCb!3992 (merged) !3331 (merged)
Edited by Marco Clemencic
This is needed to be able to build the headers in stand-alone mode, see lhcb-core/LHCbNightlyConf!984 (merged)
Part of a group: LHCb!3992 (merged) !3331 (merged)