Always treat NOTICEs received before registration as local server notices

We don't know the server's proper name until registration, so the test against
that isn't reliable.  We shouldn't be able to receive messages from anyone else
until we're registered, so this should be safe.

This requires changing serversay() to accept the from name instead of the
from_server.  While we're there, replace the use of alloca() with simpler
logic based on m_sprintf().

include/output.h

@@ -22,7 +22,7 @@
 
 	void	say (const char *, ...);
 	void	BX_bitchsay (const char *, ...);
-	void	serversay (int, int, const char *, ...);
+	void	serversay (int, const char *, const char *, ...);
 	void	BX_yell (const char *, ...);
 	void	error (const char *, ...);