diff --git a/devel/libslang/patches/patch-ac b/devel/libslang/patches/patch-ac
new file mode 100644
index 00000000000..769573c779a
--- /dev/null
+++ b/devel/libslang/patches/patch-ac
@@ -0,0 +1,12 @@
+--- autoconf/config.guess.~1~	Sun Jun  6 16:34:54 1999
++++ autoconf/config.guess	Tue Jun 22 18:19:33 1999
+@@ -324,6 +324,9 @@
+     *:NetBSD:*:*)
+ 	echo ${UNAME_MACHINE}-unknown-netbsd`echo ${UNAME_RELEASE}|sed -e 's/[-_].*/\./'`
+ 	exit 0 ;;
++    *:OpenBSD:*:*)
++	echo ${UNAME_MACHINE}-unknown-openbsd`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'`
++	exit 0 ;;
+     i*:CYGWIN*:*)
+ 	echo i386-unknown-cygwin32
+ 	exit 0 ;;