log: syslog driver

Provide a log driver that broadcasts RFC 3164 messages to syslog servers.
rsyslog is one implementation of such a server.

The messages are sent to the local broadcast address 255.255.255.255 on
port 514.

The environment variable log_hostname can be used to provide the HOSTNAME
field for the messages. The optional TIMESTAMP field of RFC 3164 is not
provided.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/Kconfig b/common/Kconfig
index 40da8fa..ee4f748 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -775,6 +775,13 @@
 	  log message is shown - other details like level, category, file and
 	  line number are omitted.
 
+config LOG_SYSLOG
+	bool "Log output to syslog server"
+	depends on LOG && NET
+	help
+	  Enables a log driver which broadcasts log records via UDP port 514
+	  to syslog servers.
+
 config LOG_TEST
 	bool "Provide a test for logging"
 	depends on LOG && UNIT_TEST