package/openrc: fix build with gcc 10

Fixes:
 - https://bugs.busybox.net/show_bug.cgi?id=13331

Cc: mscdex@mscdex.net
Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit 9d40f49dbba80da723268826487846930e61c64b)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/openrc/0006-src-rc-rc-logger.h-fix-build-failure-against-gcc-10.patch

@@ -0,0 +1,52 @@
+From 375ef42393f3dc6edbaa2cb70c79b2366072db38 Mon Sep 17 00:00:00 2001
+From: Sergei Trofimovich <slyfox@gentoo.org>
+Date: Sun, 19 Jan 2020 15:24:20 +0000
+Subject: [PATCH] src/rc/rc-logger.h: fix build failure against gcc-10
+
+On gcc-10 (and gcc-9 -fno-common) build fails as:
+
+```
+cc  -L../librc -L../libeinfo -O2 -g -std=c99 -Wall -Wextra -Wimplicit -Wshadow \
+  -Wformat=2 -Wmissing-prototypes -Wmissing-declarations -Wmissing-noreturn \
+  -Wmissing-format-attribute -Wnested-externs -Winline -Wwrite-strings \
+  -Wcast-align -Wcast-qual -Wpointer-arith -Wdeclaration-after-statement \
+  -Wsequence-point -Werror=implicit-function-declaration    \
+  -Wl,-rpath=/lib   -o openrc rc.o rc-logger.o rc-misc.o rc-plugin.o _usage.o -lutil -lrc -leinfo -Wl,-Bdynamic -ldl
+ld: rc-logger.o:/home/slyfox/dev/git/openrc/src/rc/rc-logger.h:16:
+  multiple definition of `rc_logger_pid'; rc.o:openrc/src/rc/rc-logger.h:16: first defined here
+ld: rc-logger.o:/home/slyfox/dev/git/openrc/src/rc/rc-logger.h:17:
+  multiple definition of `rc_logger_tty'; rc.o:openrc/src/rc/rc-logger.h:17: first defined here
+```
+
+gcc-10 will change the default from -fcommon to fno-common:
+https://gcc.gnu.org/PR85678.
+
+The error also happens if CFLAGS=-fno-common passed explicitly.
+
+This fixes #348.
+
+[Patch taken from upstream:
+https://github.com/OpenRC/openrc/commit/375ef42393f3dc6edbaa2cb70c79b2366072db38]
+Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
+---
+ src/rc/rc-logger.h | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/src/rc/rc-logger.h b/src/rc/rc-logger.h
+index bf6e3e57..1da294b0 100644
+--- a/src/rc/rc-logger.h
++++ b/src/rc/rc-logger.h
+@@ -13,8 +13,8 @@
+ #ifndef RC_LOGGER_H
+ #define RC_LOGGER_H
+ 
+-pid_t rc_logger_pid;
+-int rc_logger_tty;
++extern pid_t rc_logger_pid;
++extern int rc_logger_tty;
+ extern bool rc_in_logger;
+ 
+ void rc_logger_open(const char *runlevel);
+-- 
+2.20.1
+