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

Calculating dependencies ...

!!! Problem resolving dependencies for =net-analyzer/ossec-hids-3.6.0
 done!
Dependency resolution took 0.83 s (backtrack: 0/20).


!!! The ebuild selected to satisfy "=net-analyzer/ossec-hids-3.6.0" has unmet requirements.
- net-analyzer/ossec-hids-3.6.0::gentoo USE="sqlite -agent -hybrid -local -mysql -postgres -server -test"

  The following REQUIRED_USE flag constraints are unsatisfied:
    exactly-one-of ( agent hybrid local server )

  The above constraints are a subset of the following complete expression:
    exactly-one-of ( agent hybrid local server ) at-most-one-of ( mysql postgres )