[RFC PATCH 1/2] netlink: Workaround missing NETLINK_EXT_ACK define

This works around the missing NETLINK_EXT_ACK define of really really
old kernel version and defines the missing enum nlmsgerr_attrs.
---
 ell/netlink-private.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/ell/netlink-private.h b/ell/netlink-private.h
index 229b1d442ad8..0a1b016d8887 100644
--- a/ell/netlink-private.h
+++ b/ell/netlink-private.h
@@ -20,6 +20,15 @@
 #define NLA_DATA(nla)		((void*)(((char*)(nla)) + NLA_LENGTH(0)))
 #define NLA_PAYLOAD(nla)	((int)((nla)->nla_len) - NLA_LENGTH(0))
 
+#ifndef NETLINK_EXT_ACK
+#define NETLINK_EXT_ACK 11
+enum nlmsgerr_attrs {
+	NLMSGERR_ATTR_UNUSED,
+	NLMSGERR_ATTR_MSG,
+	NLMSGERR_ATTR_OFFS,
+};
+#endif
+
 bool netlink_parse_ext_ack_error(const struct nlmsghdr *nlmsg,
 					const char **out_error_msg,
 					uint32_t *out_error_offset);
-- 
2.41.0