wmaker: add support for _NET_WM_MOVERESIZE

This patch adds support for _NET_WM_MOVERESIZE hint as defined in EWMH
which allows a window without decorations to manage itself (moving/resizing).
The purpose is to fix the issue mentioned at https://github.com/window-maker/wmaker/issues/20

Tested with VS Code, Google Chrome, Steam and Discord.

Specs are available at https://specifications.freedesktop.org/wm/1.5/ar01s04.html#id-1.5.4

src/wmspec.h

@@ -28,6 +28,26 @@
 #include "window.h"
 #include <X11/Xlib.h>
 
+/*
+ * These constant provide information on the kind of window move/resize when
+ * it is initiated by the application instead of by WindowMaker. They are
+ * parameter for the client message _NET_WM_MOVERESIZE, as defined by the
+ * FreeDesktop wm-spec standard:
+ *   http://standards.freedesktop.org/wm-spec/1.5/ar01s04.html
+ */
+#define _NET_WM_MOVERESIZE_SIZE_TOPLEFT      0
+#define _NET_WM_MOVERESIZE_SIZE_TOP          1
+#define _NET_WM_MOVERESIZE_SIZE_TOPRIGHT     2
+#define _NET_WM_MOVERESIZE_SIZE_RIGHT        3
+#define _NET_WM_MOVERESIZE_SIZE_BOTTOMRIGHT  4
+#define _NET_WM_MOVERESIZE_SIZE_BOTTOM       5
+#define _NET_WM_MOVERESIZE_SIZE_BOTTOMLEFT   6
+#define _NET_WM_MOVERESIZE_SIZE_LEFT         7
+#define _NET_WM_MOVERESIZE_MOVE              8	/* movement only */
+#define _NET_WM_MOVERESIZE_SIZE_KEYBOARD     9	/* size via keyboard */
+#define _NET_WM_MOVERESIZE_MOVE_KEYBOARD    10	/* move via keyboard */
+#define _NET_WM_MOVERESIZE_CANCEL           11	/* cancel operation */
+
 void wNETWMInitStuff(WScreen *scr);
 void wNETWMCleanup(WScreen *scr);
 void wNETWMUpdateWorkarea(WScreen *scr);