Version 1.2

This release adds support for a number of new IRCv3 capabilities: CAP
302, account-tag, batch, cap-notify, labeled-response, message-tags,
setname, sts. It also enables server-time from the remote server where
available.

This release also implements a new causal.agency/consumer
vendor-specific capability which can be used by clients to ensure no
messages are missed.

The new -S bind option allows binding to a specific source address when
connecting to the remote server.

Static .mk files for cross-platform support have been replaced with a
configure script using pkg-config to set flags.