diff --git a/INSTALL b/INSTALL
index a52c4c5..e6db4b7 100644
--- a/INSTALL
+++ b/INSTALL
@@ -28,6 +28,12 @@ Extra notes:
 
 	* requires that no vendor backports interfere
 
+For ipset-5 you need:
+
+	* libmnl
+
+	* Linux kernel >= 2.6.35
+
 
 Selecting extensions
 ====================
diff --git a/configure.ac b/configure.ac
index 86eeaf1..e181930 100644
--- a/configure.ac
+++ b/configure.ac
@@ -25,7 +25,7 @@ AC_CHECK_HEADERS([linux/netfilter/x_tables.h], [],
 	[AC_MSG_ERROR([You need to have linux/netfilter/x_tables.h, see INSTALL file for details])])
 PKG_CHECK_MODULES([libxtables], [xtables >= 1.4.3])
 xtlibdir="$(pkg-config --variable=xtlibdir xtables)"
-PKG_CHECK_MODULES([libmnl], [libmnl >= 1])
+PKG_CHECK_MODULES([libmnl], [libmnl >= 1], [:], [:])
 
 AC_ARG_WITH([xtlibdir],
 	AS_HELP_STRING([--with-xtlibdir=PATH],