package/audit: fix -fno-common build failure

Added upstream patch for fixing build failure when using GCC10 as a host
compiler (-fno-common is now default).

Fixes:
http://autobuild.buildroot.net/results/c4b/c4bba80e9fc476247c7ba28850831c6a8edd559f/build-end.log

Cc: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
Reviewed-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit e7323e9d54ee9fc8a0c4af5f4198ac6024cc6b53)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/audit/0003-Header-definitions-need-to-be-external-when-building.patch

@@ -0,0 +1,28 @@
+From 017e6c6ab95df55f34e339d2139def83e5dada1f Mon Sep 17 00:00:00 2001
+From: Steve Grubb <sgrubb@redhat.com>
+Date: Fri, 10 Jan 2020 21:13:50 -0500
+Subject: [PATCH] Header definitions need to be external when building with
+ -fno-common (which is default in GCC 10) - Tony Jones
+
+Patch taken from upstream: https://github.com/linux-audit/audit-userspace/commit/017e6c6ab95df55f34e339d2139def83e5dada1f
+Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
+---
+ src/ausearch-common.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/ausearch-common.h b/src/ausearch-common.h
+index 6669203..3040547 100644
+--- a/src/ausearch-common.h
++++ b/src/ausearch-common.h
+@@ -50,7 +50,7 @@ extern pid_t event_pid;
+ extern int event_exact_match;
+ extern uid_t event_uid, event_euid, event_loginuid;
+ extern const char *event_tuid, *event_teuid, *event_tauid;
+-slist *event_node_list;
++extern slist *event_node_list;
+ extern const char *event_comm;
+ extern const char *event_filename;
+ extern const char *event_hostname;
+-- 
+2.20.1
+