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

[ebuild  N     ] net-p2p/bitcoind-0.10_pre20141204::bitcoin USE="extras upnp wallet -examples -logrotate {-test}" BITCOIN_POLICY="cpfp spamfilter" 0 kB

Total: 1 package (1 new), Size of downloads: 0 kB

Would you like to merge these packages? [Yes/No]

>>> Verifying ebuild manifests
>>> Running pre-merge checks for net-p2p/bitcoind-0.10_pre20141204
* Extra functionality improvements to Bitcoin Core are enabled.
* CPFP policy is enabled: If you mine, you will give consideration to child transaction fees to pay for their parents.
* Enhanced spam filter policy is enabled: Notorious spammers will not be assisted by your node.
* For more information, see http://luke.dashjr.org/programs/bitcoin/files/bitcoind/luke-jr/0.10.x/0.10_pre20141204.ljr-20141204/bitcoin-0.10_pre20141204.ljr-20141204.desc.txt

>>> Emerging (1 of 1) net-p2p/bitcoind-0.10_pre20141204 from bitcoin