diff -Nur harfbuzz-1.2.6-orig/src/check-header-guards.sh harfbuzz-1.2.6-aix/src/check-header-guards.sh
--- harfbuzz-1.2.6-orig/src/check-header-guards.sh	2016-01-06 13:00:36 +0100
+++ harfbuzz-1.2.6-aix/src/check-header-guards.sh	2016-04-22 14:44:06 +0200
@@ -13,7 +13,7 @@
 	test -f "$srcdir/$x" && x="$srcdir/$x"
 	echo "$x" | grep -q '[^h]$' && continue;
 	xx=`echo "$x" | sed 's@.*/@@'`
-	tag=`echo "$xx" | tr 'a-z.-' 'A-Z_'`
+	tag=`echo "$xx" | tr 'a-z.-' 'A-Z__'`
 	lines=`grep -w "$tag" "$x" | wc -l | sed 's/[ 	]*//g'`
 	if test "x$lines" != x3; then
 		echo "Ouch, header file $x does not have correct preprocessor guards"