Incorrect minimum glib-2.0 version in configure.ac
Modified configure.ac to emit warnings.
$ make 2>&1 | grep "Not available"
dmap-control-share.c:107:1: warning: ‘g_type_add_instance_private’ is deprecated: Not available before 2.38 [-Wdeprecated-declarations]
dmap-connection.c:87:1: warning: ‘g_type_add_instance_private’ is deprecated: Not available before 2.38 [-Wdeprecated-declarations]
dmap-mdns-service.c:137:1: warning: ‘g_type_add_instance_private’ is deprecated: Not available before 2.38 [-Wdeprecated-declarations]
dmap-share.c:126:1: warning: ‘g_type_add_instance_private’ is deprecated: Not available before 2.38 [-Wdeprecated-declarations]
dmap-image-share.c:111:1: warning: ‘g_type_add_instance_private’ is deprecated: Not available before 2.38 [-Wdeprecated-declarations]
dmap-mdns-publisher-dnssd.c:42:1: warning: ‘g_type_add_instance_private’ is deprecated: Not available before 2.38 [-Wdeprecated-declarations]