Add the xcb_connection_t to session_t

Signed-off-by: Uli Schlachter <psychon@znc.in>
Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/x.h

@@ -24,6 +24,18 @@ typedef struct winprop winprop_t;
   r; \
 })
 
+/**
+ * Send a request to X server and get the reply to make sure all previous
+ * requests are processed, and their replies received
+ *
+ * xcb_get_input_focus is used here because it is the same request used by
+ * libX11
+ */
+static inline void
+x_sync(xcb_connection_t *c) {
+  free(xcb_get_input_focus_reply(c, xcb_get_input_focus(c), NULL));
+}
+
 /**
  * Get a specific attribute of a window.
  *