Break syslog_channel.c up into syslog_channel.c, syslog_putc.c, syslog_force.c...

Break syslog_channel.c up into syslog_channel.c, syslog_putc.c, syslog_force.c and syslog_flush.c to limited what is brought into the link.  Separate syslog_emergstream.c from syslog_stream.c.  Didn't help in the case I was looking at.