I understand that xxx.BitcoinMiner is a false positive, but what about Trojan.IRCbot and others?
Looks not like false positive to me
Those are false positives. It's using the IRC method to obtain seed nodes. AV's do not like this code as it is often used by botnets for control. You can add an exception in your antivirus program quite safely.
By the way, isn't IRC seeding supposed to be removed in the current version? In github trunk it is anyway, and replaced with DNS seed (which still does not work: the DNS server does not respond).