These are the packages that would be merged, in order:

Calculating dependencies ...

!!! Problem resolving dependencies for =dev-db/pgrouting-3.6.2
 done!
Dependency resolution took 0.85 s (backtrack: 0/20).


!!! The ebuild selected to satisfy "=dev-db/pgrouting-3.6.2" has unmet requirements.
- dev-db/pgrouting-3.6.2::gentoo USE="" POSTGRES_TARGETS="-postgres14 -postgres15 -postgres16"

  The following REQUIRED_USE flag constraints are unsatisfied:
    any-of ( postgres_targets_postgres16 postgres_targets_postgres15 postgres_targets_postgres14 )