libpfring: disable libnl

When libnl is built, libpfring links against it. This causes the build
to fail due to a missing dependency. Disable libnl to avoid this.

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>

libs/libpfring/Makefile

@@ -56,7 +56,8 @@ define Build/InstallDev
 endef
 
 CONFIGURE_VARS += \
-	MACHINE="$(ARCH)"
+	MACHINE="$(ARCH)" \
+	ac_cv_lib_nl_3_nl_socket_alloc=no
 
 define Package/libpfring/install
 	$(INSTALL_DIR) $(1)/usr/lib/