applied Ivan Delalande's NET_SUPPORTING_WM_CHECK patch for gtk3 compatibility

dwm.c

@@ -61,7 +61,7 @@
 /* enums */
 enum { CurNormal, CurResize, CurMove, CurLast }; /* cursor */
 enum { SchemeNorm, SchemeSel }; /* color schemes */
-enum { NetSupported, NetWMName, NetWMState,
+enum { NetSupported, NetWMName, NetWMState, NetWMCheck,
        NetWMFullscreen, NetActiveWindow, NetWMWindowType,
        NetWMWindowTypeDialog, NetClientList, NetLast }; /* EWMH atoms */
 enum { WMProtocols, WMDelete, WMState, WMTakeFocus, WMLast }; /* default atoms */
@@ -267,7 +267,7 @@ static Scm *scheme;
 static Display *dpy;
 static Drw *drw;
 static Monitor *mons, *selmon;
-static Window root;
+static Window root, wmcheckwin;
 
 /* configuration, allows nested code to access above variables */
 #include "config.h"
@@ -485,6 +485,7 @@ cleanup(void)
 		drw_cur_free(drw, cursor[i]);
 	for (i = 0; i < LENGTH(colors); i++)
 		free(scheme[i]);
+	XDestroyWindow(dpy, wmcheckwin);
 	drw_free(drw);
 	XSync(dpy, False);
 	XSetInputFocus(dpy, PointerRoot, RevertToPointerRoot, CurrentTime);
@@ -1551,6 +1552,7 @@ setup(void)
 {
 	int i;
 	XSetWindowAttributes wa;
+	Atom utf8string;
 
 	/* clean up any zombies immediately */
 	sigchld(0);
@@ -1567,6 +1569,7 @@ setup(void)
 	bh = drw->fonts->h + 2;
 	updategeom();
 	/* init atoms */
+	utf8string = XInternAtom(dpy, "UTF8_STRING", False);
 	wmatom[WMProtocols] = XInternAtom(dpy, "WM_PROTOCOLS", False);
 	wmatom[WMDelete] = XInternAtom(dpy, "WM_DELETE_WINDOW", False);
 	wmatom[WMState] = XInternAtom(dpy, "WM_STATE", False);
@@ -1575,6 +1578,7 @@ setup(void)
 	netatom[NetSupported] = XInternAtom(dpy, "_NET_SUPPORTED", False);
 	netatom[NetWMName] = XInternAtom(dpy, "_NET_WM_NAME", False);
 	netatom[NetWMState] = XInternAtom(dpy, "_NET_WM_STATE", False);
+	netatom[NetWMCheck] = XInternAtom(dpy, "_NET_SUPPORTING_WM_CHECK", False);
 	netatom[NetWMFullscreen] = XInternAtom(dpy, "_NET_WM_STATE_FULLSCREEN", False);
 	netatom[NetWMWindowType] = XInternAtom(dpy, "_NET_WM_WINDOW_TYPE", False);
 	netatom[NetWMWindowTypeDialog] = XInternAtom(dpy, "_NET_WM_WINDOW_TYPE_DIALOG", False);
@@ -1590,6 +1594,14 @@ setup(void)
 	/* init bars */
 	updatebars();
 	updatestatus();
+	/* supporting window for NetWMCheck */
+	wmcheckwin = XCreateSimpleWindow(dpy, root, 0, 0, 1, 1, 0, 0, 0);
+	XChangeProperty(dpy, wmcheckwin, netatom[NetWMCheck], XA_WINDOW, 32,
+		PropModeReplace, (unsigned char *) &wmcheckwin, 1);
+	XChangeProperty(dpy, wmcheckwin, netatom[NetWMName], utf8string, 8,
+		PropModeReplace, (unsigned char *) "dwm", 4);
+	XChangeProperty(dpy, root, netatom[NetWMCheck], XA_WINDOW, 32,
+		PropModeReplace, (unsigned char *) &wmcheckwin, 1);
 	/* EWMH support per view */
 	XChangeProperty(dpy, root, netatom[NetSupported], XA_ATOM, 32,
 			PropModeReplace, (unsigned char *) netatom, NetLast);