Add syslog_split_messages parameter

Reviewed-by: Andreas Karlsson <andreas@proxel.se>

src/backend/utils/misc/postgresql.conf.sample

@@ -359,6 +359,7 @@
 #syslog_facility = 'LOCAL0'
 #syslog_ident = 'postgres'
 #syslog_sequence_numbers = on
+#syslog_split_messages = on
 
 # This is only relevant when logging to eventlog (win32):
 #event_source = 'PostgreSQL'