This was created partially out of frustration with the lack of a quality IRC client library. I guess maybe I'm just too picky...
The goal of libunicorn is to provide a flexible API for dealing with the IRC protocol. While the focus is on clients, libunicorn is flexible enough to be used by servers as well (even TS6 servers where libunicorn has no knowledge of TS6). libunicorn's primary functionality lies in its parsers and formatters which convert IRC messages (as described by the grammar in RFC 1459) to and from C strings. In theory, any protocol which uses IRC-like messages (i.e. ":sender COMMAND arg arg :long arg") could make use of the parsers and formatters in libunicorn.
This project is licensed under the MIT license, contained in the COPYING file.
The official libunicorn channel is irc.staticbox.net #alicorn
libunicorn currently depends only on libmowgli-2. Although libunicorn only uses a small subset of the features in libmowgli-2, the library was created to be used with applications that will make use of libmowgli-2.
This library is not very well-documented, but the source is simple enough and the functions named sensibly enough that a quick stroll through the various .h and .c files should be adequate to your understanding.
$ aclocal -I m4
$ autoconf
$ automake --foreign --add-missing
[ignore anything that looks like an error here]
$ ./configure
$ make
$ sudo make install