Build problems when compiling with c++20

When building with support of c++20 on several stages compilation fails with messages of type:

error: incomplete type 'FairRootManager' used in nested name specifier

or

error: unknown type name 'TClonesArray'

or

error: expected unqualified-id before 'void' IntervalTree<T, K>(void)
                                                                ^~~~ 

These come either from missing includes that appeared before "automagically" or from having template types which should not be there.