x11/libxkbcommon: swtch to legacy rules on 11

x11/libxkbcommon was switched to use evdev rules in r528813, but FreeBSD 11
still needs the legacy rules.  Switch back to the legacy rules, but only on
FreeBSD 11.
Adjust the UPDATING entry to indicate that the switch to evdev rules by
default is only on FreeBSD 12 and later, and that FreeBSD 11 still uses the
legacy rules.

UPDATING

@@ -26,15 +26,15 @@ you update your ports collection, before attempting any port upgrades.
 
   The libxkbcommon library (x11/libxkbcommon), used to handle keyboards
   in some applications, most notably kde and wayland, have been switched
-  to use evdev rules by default.  Some keys, most notably arrow keys, 
-  may not work in applications using libxkbcommon if you are using
-  xf86-input-keyboard rather than xf86-input-libinput.
+  to use evdev rules by default on FreeBSD 12 and later.  Some keys, most
+  notably arrow keys, may not work in applications using libxkbcommon if
+  you are using xf86-input-keyboard rather than xf86-input-libinput.
   If you have trouble with the keyboard keys, and if /var/log/Xorg.*.log
   shows that the "kbd" or "keyboard" driver is being used, you need to
   switch to legacy rules by setting the environment variable
   XKB_DEFAULT_RULES to xorg.
   This switch is made to match the default configuration on FreeBSD 12.1 and
-  later, the default configuration on FreeBSD 11.3 still requres the legacy
+  later, the default configuration on FreeBSD 11.3 still uses the legacy
   rules.
 
 20200316:

x11/libxkbcommon/Makefile

@@ -2,7 +2,7 @@
 
 PORTNAME=	libxkbcommon
 PORTVERSION=	0.10.0
-PORTREVISION=	1
+PORTREVISION=	2
 CATEGORIES=	x11
 MASTER_SITES=	https://xkbcommon.org/download/
 DIST_SUBDIR=	xorg/lib
@@ -21,4 +21,10 @@ MESON_ARGS=	-Denable-docs=false \
 		-Denable-wayland=false \
 		-Dx-locale-root="${PREFIX}/lib/X11/locale"
 
-.include <bsd.port.mk>
+.include <bsd.port.pre.mk>
+
+.if ${OSVERSION} < 1200000
+MESON_ARGS+=	-Ddefault-rules=xorg
+.endif
+
+.include <bsd.port.post.mk>