In the deserialise function, GUnixFDMessage was comparing 'level' to
both SOL_SOCKET and SCM_RIGHTS. It is correct to compare 'type' to
SCM_RIGHTS. The code passed tests only because:
1) it's a "should always be OK" double-check
2) SOL_SOCKET and SCM_RIGHTS, by chance, both have the value '1' on
Linux systems.
This adds:
GInitable - failable object constructor interface
GAsyncInitable - async failable object constructor interface
GSocket - Platform independent lowlevel berkely socket style object
GSocketControlMessage - For passing control messages over GSocket
GUnixFDMessage - unix fd passing socket control message
Some changes were done during the import from gnio to make things
work in glib. For instance, types were moved to other headers, header
file boiler plate were updated to glib style and gio.symbols stuff
was added.
