io: introduce qio_channel_create_socket_watch

Sockets are not in the same namespace as file descriptors on Windows.
As an initial step, introduce separate APIs for file descriptor and
socket watches.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/io/channel-watch.c b/io/channel-watch.c
index 5373605..dfac8f8 100644
--- a/io/channel-watch.c
+++ b/io/channel-watch.c
@@ -172,6 +172,21 @@
     return source;
 }
 
+#ifdef CONFIG_WIN32
+GSource *qio_channel_create_socket_watch(QIOChannel *ioc,
+                                         int socket,
+                                         GIOCondition condition)
+{
+    abort();
+}
+#else
+GSource *qio_channel_create_socket_watch(QIOChannel *ioc,
+                                         int socket,
+                                         GIOCondition condition)
+{
+    return qio_channel_create_fd_watch(ioc, socket, condition);
+}
+#endif
 
 GSource *qio_channel_create_fd_pair_watch(QIOChannel *ioc,
                                           int fdread,