Index: postinstall
===================================================================
--- postinstall	12 Aug 2014 09:12:18 -0000	1.179
+++ postinstall	14 Aug 2014 09:15:58 -0000
@@ -728,7 +728,22 @@ get_makevar()
 detect_x11()
 {
 	if $SOURCEMODE; then
-		get_makevar MKX11 X11ROOTDIR X11SRCDIR
+		if [ -n "${XSRC_DIR}" ]; then
+			# -x XSRC_DIR on command line forces MKX11=yes
+			# and forces X11SRCDIR, but X11ROOTDIR comes
+			# from get_makevar.
+			MKX11=yes
+			X11SRCDIR="${XSRC_DIR}"
+			get_makevar X11ROOTDIR
+		else
+			# No -x on command line.  Use get_makevar, and
+			# set XSRC_DIR according to the result.
+			get_makevar MKX11 X11ROOTDIR X11SRCDIR
+			case "${MKX11:-no}" in
+			[yY][eE][sS]) XSRC_DIR="${X11SRCDIR}" ;;
+			esac
+
+		fi
 	else
 		if [ -f "${SRC_DIR}/etc/mtree/set.xetc" ]; then
 			MKX11=yes
@@ -738,6 +753,9 @@ detect_x11()
 			X11ROOTDIR=
 		fi
 		X11SRCDIR=/nonexistent/xsrc
+		if [ -n "${XSRC_DIR}" ]; then
+			err 2 "-x option is allowed only in source mode"
+		fi
 	fi
 }
 
@@ -938,6 +956,9 @@ do_fontconfig()
 	if ! $SOURCEMODE; then
 		FONTCONFIG_DIR="${SRC_DIR}/etc/fonts/conf.avail" 
 	else
+		if [ -z "${XSRC_DIR}" ]; then
+			msg "No xsrc dir; skipping fontconfig check"
+		fi
 		FONTCONFIG_DIR="${XSRC_DIR}/external/mit/fontconfig/dist/conf.d"
 	fi
 
@@ -2053,7 +2074,7 @@ Usage: ${PROGNAME} [-s srcdir] [-x xsrcd
 							[${SRC_DIR:-/usr/src}]
 	-x xsrcdir      Location of the X11 source files.  This must be
 			a directory that contains a NetBSD xsrc tree.
-							[${XSRC_DIR:-/usr/src/../xsrc}]
+							[automatic]
 	-d destdir	Destination directory to check. [${DEST_DIR:-/}]
 	-m mach		MACHINE.			[${MACHINE}]
 	-a arch		MACHINE_ARCH.			[${MACHINE_ARCH}]
@@ -2096,7 +2117,7 @@ main()
 	TGZLIST=		# quoted list list of tgz files
 	SRC_ARGLIST=		# quoted list of one or more "-s" args
 	SRC_DIR="${SRC_ARG}"	# set default value for early usage()
-	XSRC_DIR="${SRC_ARG}/../xsrc"
+	XSRC_DIR=""
 	N_SRC_ARGS=0		# number of "-s" args
 	TGZMODE=false		# true if "-s" specifies a tgz file
 	DIRMODE=false		# true if "-s" specified a directory
Index: postinstall.8
===================================================================
--- postinstall.8	15 Aug 2012 16:21:41 -0000	1.16
+++ postinstall.8	14 Aug 2014 09:25:43 -0000
@@ -27,7 +27,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd August 15, 2012
+.Dd August 14, 2014
 .Dt POSTINSTALL 8
 .Os
 .Sh NAME
@@ -39,6 +39,7 @@
 .Op Fl d Ar destdir
 .Op Fl m Ar machine
 .Op Fl s Brq Ar srcdir | Ar tgzdir | Ar tgzfile
+.Op Fl x Ar xsrcdir
 .Ar operation
 .Op Ar item Op ...
 .Sh DESCRIPTION
@@ -118,6 +119,24 @@ The
 .Dq Pa xetc.tgz
 set file is optional.
 .El
+.It Fl x Ar xsrcdir
+Location of the X11 source files.
+If specified, this must be a directory that contains a
+.Nx
+.Sy xsrc
+tree.
+This option is valid only in source mode (when the
+.Fl s
+option specifies a directory that contains a
+.Nx
+.Sy src
+tree).
+By default, this is derived from the
+.Ev MKX11
+and
+.Ev X11SRCDIR
+variables in the environment and
+.Xr mk.conf 5 .
 .El
 .Pp
 The