Update buildroot to 2021.02.4 (#1522)

Signed-off-by: Stefan Agner <stefan@agner.ch>

buildroot/package/keepalived/0001-core-Fix-compiling-on-RHEL-9.patch

@@ -0,0 +1,34 @@
+From 3fd0c21e4f63ac0a52b5d7a09575f0f364972e4d Mon Sep 17 00:00:00 2001
+From: Quentin Armitage <quentin@armitage.org.uk>
+Date: Tue, 8 Jun 2021 08:57:45 +0100
+Subject: [PATCH] core: Fix compiling on RHEL 9
+
+Signed-off-by: Quentin Armitage <quentin@armitage.org.uk>
+
+[Retrieved from:
+https://github.com/acassen/keepalived/commit/3fd0c21e4f63ac0a52b5d7a09575f0f364972e4d]
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ keepalived/core/layer4.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/keepalived/core/layer4.c b/keepalived/core/layer4.c
+index d2cc971a3..fdca04913 100644
+--- a/keepalived/core/layer4.c
++++ b/keepalived/core/layer4.c
+@@ -27,13 +27,14 @@
+ #include <errno.h>
+ #include <unistd.h>
+ #include <fcntl.h>
++#include <netinet/in.h>
++#include <net/if.h>
+ #include <linux/icmp.h>
+ #include <linux/icmpv6.h>
+ #ifdef ERRQUEUE_NEEDS_SYS_TIME
+ #include <sys/time.h>
+ #endif
+ #include <linux/errqueue.h>
+-#include <netinet/in.h>
+ 
+ #include "layer4.h"
+ #include "logger.h"