WPrefs: Ignore NumLock key when capturing keyboard shortcuts

This patch includes the function "NumLockMask", that checks if the
Alt Modifier key is "NumLock". Then we can use this function in the
calls to Capture the key sequence and don't use this modifier.

WPrefs.app/KeyboardShortcuts.c

@@ -262,6 +262,22 @@ static void XConvertCase(register KeySym sym, KeySym * lower, KeySym * upper)
 }
 #endif
 
+static int NumLockMask(Display *dpy)
+{
+	int i;
+	XModifierKeymap *map = XGetModifierMapping(dpy);
+	KeyCode numlock_keycode = XKeysymToKeycode(dpy, XK_Num_Lock);
+	if (numlock_keycode == NoSymbol)
+		return 0;
+
+	for (i = 0; i < 8; i++) {
+		if (map->modifiermap[map->max_keypermod * i] == numlock_keycode)
+			return 1 << i;
+	}
+
+	return 0;
+}
+
 char *capture_shortcut(Display *dpy, Bool *capturing, Bool convert_case)
 {
 	XEvent ev;
@@ -297,27 +313,27 @@ char *capture_shortcut(Display *dpy, Bool *capturing, Bool convert_case)
 
 	buffer[0] = 0;
 
-	if (ev.xkey.state & ControlMask) {
+	if (ev.xkey.state & ControlMask)
 		strcat(buffer, "Control+");
-	}
-	if (ev.xkey.state & ShiftMask) {
+
+	if (ev.xkey.state & ShiftMask)
 		strcat(buffer, "Shift+");
-	}
-	if (ev.xkey.state & Mod1Mask) {
+
+	if ((ev.xkey.state & Mod1Mask) && !NumLockMask(dpy))
 		strcat(buffer, "Mod1+");
-	}
-	if (ev.xkey.state & Mod2Mask) {
+
+	if ((ev.xkey.state & Mod2Mask) && !NumLockMask(dpy))
 		strcat(buffer, "Mod2+");
-	}
-	if (ev.xkey.state & Mod3Mask) {
+
+	if ((ev.xkey.state & Mod3Mask) && !NumLockMask(dpy))
 		strcat(buffer, "Mod3+");
-	}
-	if (ev.xkey.state & Mod4Mask) {
+
+	if ((ev.xkey.state & Mod4Mask) && !NumLockMask(dpy))
 		strcat(buffer, "Mod4+");
-	}
-	if (ev.xkey.state & Mod5Mask) {
+
+	if ((ev.xkey.state & Mod5Mask) && !NumLockMask(dpy))
 		strcat(buffer, "Mod5+");
-	}
+
 	strcat(buffer, key);
 
 	return wstrdup(buffer);