A lot of tests in gio/tests/ don't have a license header.

https://bugzilla.gnome.org/show_bug.cgi?id=776504

The static analyser (correctly) considers a type check to fail if the
variable is NULL. In this case, the address must be non-NULL as no error
was thrown by g_socket_connection_get_remote_address(), but the static
analyser doesn’t know this.

Add a non-NULL assertion anyway, both to shut the analyser up, and
because it’s good extra testing.

Found by scan-build.

https://bugzilla.gnome.org/show_bug.cgi?id=113075

Although none of the in-tree GSocketConnectable types need it, other
types (like SoupAddress) may find it useful to be able to pass a URI
and a default-port to GProxyAddressEnumerator separately (the same way
you can with GNetworkAddress). So add a default-port property.

https://bugzilla.gnome.org/show_bug.cgi?id=698877

Add a proxy-resolver property to GSocketClient, to allow overriding
proxy resolution in situations where you need to force a particular
proxy rather than using the system defaults.

https://bugzilla.gnome.org/show_bug.cgi?id=691105

Otherwise we fail to build with -Werror=missing-prototypes.

https://bugzilla.gnome.org/show_bug.cgi?id=687385

Very many testcases, some GLib tools (resource compiler, etc) and
GApplication were calling g_type_init().

Remove those uses, as they are no longer required.

https://bugzilla.gnome.org/show_bug.cgi?id=686161

https://bugzilla.gnome.org/show_bug.cgi?id=661767

https://bugzilla.gnome.org/show_bug.cgi?id=682560