diff --git a/lib/libsysdecode/mkioctls b/lib/libsysdecode/mkioctls
index 03f53ead642..05ae930888a 100644
--- a/lib/libsysdecode/mkioctls
+++ b/lib/libsysdecode/mkioctls
@@ -17,19 +17,30 @@ LC_ALL=C; export LC_ALL
 # XXX should we use an ANSI cpp?
 ioctl_includes=$(
 	cd $includedir
-
-	filter='tee'
-	if [ "${MK_PF}" == "no" ]; then
-		filter='egrep -v (net/pfvar|net/if_pfsync)\.h'
+	set -e
+	# if /bin/sh is bash this will avoid further errors due to missing commands
+	if set -o | grep -q pipefail; then
+		set -o pipefail
 	fi
 
-	find -H -s * -name '*.h' | \
+	filter='tee'
+	if [ "${MK_PF}" = "no" ]; then
+		filter='egrep -v (net/pfvar|net/if_pfsync)\.h'
+	fi
+	# find -s would avoid the need to invoke sort but it is non-portable
+	find -L ./* -type f -name '*.h' | \
+		LC_ALL=C sort | \
 		$filter | \
 		xargs egrep -l \
 '^#[ 	]*define[ 	]+[A-Za-z_][A-Za-z0-9_]*[ 	]+_IO[^a-z0-9_]' |
 		awk '{printf("#include <%s>\\n", $1)}'
 )
 
+if [ -z "$ioctl_includes" ]; then
+	echo "Failed to build list of ioctl headers"
+	exit 1
+fi
+
 awk -v x="$ioctl_includes" 'BEGIN {print x}' |
 	$CPP -nostdinc -I$includedir -dM -DCOMPAT_43TTY - |
 	awk -v ioctl_includes="$ioctl_includes" '