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

Calculating dependencies ...

!!! Problem resolving dependencies for =net-proxy/privoxy-4.0.0
 done!
Dependency resolution took 0.82 s (backtrack: 0/20).


!!! The ebuild selected to satisfy "=net-proxy/privoxy-4.0.0" has unmet requirements.
- net-proxy/privoxy-4.0.0::gentoo USE="acl fast-redirects force image-blocking ipv6 jit mbedtls openssl ssl stats threads zlib -brotli -client-tags -compression -editor -extended-host-patterns -extended-statistics -external-filters -fuzz -graceful-termination -lfs -png-images -sanitize (-selinux) -toggle -tools -whitelists"

  The following REQUIRED_USE flag constraints are unsatisfied:
    ssl? ( exactly-one-of ( mbedtls openssl ) )

  The above constraints are a subset of the following complete expression:
    brotli? ( zlib ) client-tags? ( threads ) compression? ( zlib ) extended-statistics? ( threads ) fuzz? ( zlib ) ssl? ( exactly-one-of ( mbedtls openssl ) threads ) toggle? ( editor )