router/rfc822.c and local mail via SMTP

[Michael Richardson <mcr@sandelman.ocunix.on.ca>]

  While tracing through router/rfc822.c to try and determine why
FYI_BREAKIN is being flagged when MH posts mail via SMTP through the
loopback device, I've come upon what must be a bug...

  In mkSender(), the variable 'h' (of type struct header *), is  teded
very early on to be !=NULL, yet it is not assigned in that function. 
  C makes no guarantees about initializing automatic variables,
(particularly register ones in this case), so the tests !=NULL may or
may not be no-ops.
  There is another variable 'sh' of the same type that *is* used. A
mixup Rayan?
  Thanks.