Support for UNIX-domain (also known as local) sockets.
UNIX domain sockets are generally visible in the filesystem. However, some systems support abstract socket names which are not visible in the filesystem and not affected by the filesystem permissions, visibility, etc. Currently this is only supported under Linux. If you attempt to use abstract sockets on other systems, function calls may return g_io_error_not_supported errors. You can use abstract_names_supported to see if abstract names are supported.
Note that `<gio/gunixsocketaddress.h>` belongs to the UNIX-specific GIO interfaces, thus you have to use the `gio-unix-2.0.pc` pkg-config file when using it.