Require automake 1.12

We use macros from 1.12 anyway.
interfaces: License was meant to be the same as the rest
nice: Auto-substitute pkg-config requirements in nice.pc.in

The requirements in the pkg-config file were outdated and incomplete. It
makes a lot more sense to automatically substitute them in from the
checks in configure.ac.
nice: Expose UPnP support in nice.pc.in

It might be useful for dependent packages to check whether libnice was
compiled with UPnP support, so expose that as a variable in the
pkg-config file, set to ‘true’ if supported, and the empty string
otherwise.
build: Add GObject introspection support

This bumps our autoconf requirement to 2.62 (from 2.59c) and disables
automake portability warnings.

It does not introduce a hard dependency on gobject-introspection; but if
available, it requires version 1.30.0. Support can be enabled with
--enable-introspection, and is required to make distcheck.

The generated introspection file has not been checked thoroughly, and
may expose internal symbols. A lot of new annotations are needed to make
many of the symbols usable.
agent: Fix badly formatted gtk-doc comments
agent: Add missing (element-type) annotations to gtk-doc comments

These make the GSLists usable from introspection.
agent: Fix a typo in a documentation comment
agent: Mark nice_agent_attach_recv() as (skip)

This removes it from the introspected bindings. It is unintrospectable
because it specifies a callback (@func) which persists after the
nice_agent_attach_recv() call returns. This is only supported by
gobject-introspection if a full closure with GDestroyNotify callback for
the user is passed in too.
agent: Add missing #includes to candidate.h
build: Add the lcov directory to .gitignore
agent: Fix typos in documentation
agent: Add a missing field documentation comment
docs: Remove some private symbols from the documentation sections file
agent: Add a missing precondition assertion

Spotted by Tartan.
examples: Remove unnecessary dynamic type casts

We know the agent is a GObject — there is no need to check it at
runtime. This also improves Tartan’s static analysis of signal
connections.
socket: Avoid g_main_context_ref(NULL) calls using the default context

If (agent->main_context == NULL) the sockets are created with a NULL
main context, which they then try to ref. That does not end well.
introspection: Rename gir file to match library version
agent: Factor our writability signal
outputstream: Fix reference leak