Don’t rely on libxcb-wm any longer, as it got removed in libxcb 0.3.4

See http://cgit.freedesktop.org/xcb/util/commit/?id=4c9a707f472e49bc3005354db265a0214071d46b

include/i3.h

@@ -9,11 +9,13 @@
  *
  */
 #include <xcb/xcb.h>
+#include <xcb/xcb_property.h>
 #include <xcb/xcb_event.h>
 
 #include <X11/XKBlib.h>
 
 #include "queue.h"
+#include "data.h"
 
 #ifndef _I3_H
 #define _I3_H
@@ -28,4 +30,9 @@ extern xcb_event_handlers_t evenths;
 extern int num_screens;
 extern xcb_atom_t atoms[NUM_ATOMS];
 
+void manage_window(xcb_property_handlers_t *prophs, xcb_connection_t *conn, xcb_window_t window, window_attributes_t wa);
+void reparent_window(xcb_connection_t *conn, xcb_window_t child,
+                     xcb_visualid_t visual, xcb_window_t root, uint8_t depth,
+                     int16_t x, int16_t y, uint16_t width, uint16_t height);
+
 #endif