switch amd64, i386, shark, ofppc and macppc to xorg-server 1.18.

add a note to UPDATING about needing a clean objdir and destdir.

UPDATING

@@ -1,4 +1,4 @@
-$NetBSD: UPDATING,v 1.272 2016/05/30 03:11:48 dholland Exp $
+$NetBSD: UPDATING,v 1.273 2016/09/15 07:49:08 mrg Exp $
 
 This file (UPDATING) is intended to be a brief reference to recent
 changes that might cause problems in the build process, and a guide for
@@ -19,6 +19,11 @@ See also: BUILDING, build.sh, Makefile.
 Recent changes:
 ^^^^^^^^^^^^^^^
 
+20160914:
+	i386, amd64, shark, ofppc and macppc have joined shark and x68k
+	ports in using xorg-server 1.18. This requires a clean destdir
+	and a clean objdir.
+
 20160527:
 	i386 needs a full cleandir or objdir deletion because PIE has
 	been enabled. (see the amd64 entry two down for further info)

share/mk/bsd.own.mk

@@ -1,4 +1,4 @@
-#	$NetBSD: bsd.own.mk,v 1.955 2016/09/11 04:59:54 tsutsui Exp $
+#	$NetBSD: bsd.own.mk,v 1.956 2016/09/15 07:49:08 mrg Exp $
 
 # This needs to be before bsd.init.mk
 .if defined(BSD_MK_COMPAT_FILE)
@@ -1391,7 +1391,12 @@ X11SRCDIR.${_proto}proto?=		${X11SRCDIRMIT}/${_proto}proto/dist
 .endfor
 
 # During transition from xorg-server 1.10 to 1.18
-.if ${MACHINE} == "shark"	|| \
+.if \
+    ${MACHINE_ARCH} == "x86_64" || \
+    ${MACHINE_ARCH} == "i386"   || \
+    ${MACHINE} == "ofppc"	|| \
+    ${MACHINE} == "macppc"	|| \
+    ${MACHINE} == "shark"	|| \
     ${MACHINE} == "x68k"
 HAVE_XORG_SERVER_VER?=118
 .else