Map ('5') and allow mod5mask (altgr) as a modifier.

From Artturi Alm (though changed from 'm' to '5')

conf.c

@@ -197,10 +197,11 @@ static const struct {
 	const char	ch;
 	int		mask;
 } bind_mods[] = {
+	{ 'S',	ShiftMask },
 	{ 'C',	ControlMask },
 	{ 'M',	Mod1Mask },
 	{ '4',	Mod4Mask },
-	{ 'S',	ShiftMask },
+	{ '5',	Mod5Mask },
 };
 static const struct {
 	const char	*key;

cwmrc.5

@@ -84,6 +84,8 @@ Meta key.
 Shift key.
 .It Ic 4
 Mod4 (windows) key.
+.It Ic 5
+Mod5 (AltGr) key.
 .El
 .Pp
 The
@@ -101,18 +103,10 @@ The modifier keys come first, followed by a
 .Sq - ,
 then the button number.
 .Pp
-The following modifiers are recognised:
-.Pp
-.Bl -tag -width Ds -offset indent -compact
-.It Ic C
-Control key.
-.It Ic M
-Meta key.
-.It Ic S
-Shift key.
-.It Ic 4
-Mod4 (windows) key.
-.El
+The same modifiers are recognised as for
+.Ar key
+in
+.Nm bind-key .
 .Pp
 The following buttons are recognised:
 .Pp

xevents.c

@@ -69,7 +69,7 @@ void		(*xev_handlers[LASTEvent])(XEvent *) = {
 };
 
 static KeySym modkeys[] = { XK_Alt_L, XK_Alt_R, XK_Super_L, XK_Super_R,
-			    XK_Control_L, XK_Control_R };
+			    XK_Control_L, XK_Control_R, XK_ISO_Level3_Shift };
 
 static void
 xev_handle_maprequest(XEvent *ee)