Refactor/order the handling of reply-to-message header data

Fix CID 551210

There should not be any change in behavior here other than eliminating a
potential null pointer dereference.

src/sbbs3/postmsg.cpp

@@ -100,22 +100,21 @@ bool sbbs_t::postmsg(int subnum, int wm_mode, smb_t* resmb, smbmsg_t* remsg)
 			SAFECOPY(from, text[Anonymous]);
 		else
 			SAFECOPY_UTF8(from, msghdr_field(remsg, remsg->from, NULL, term->charset() == CHARSET_UTF8));
+		SAFECOPY_UTF8(touser, from);
 		// If user posted this message, reply to the original recipient again
-		if (remsg->to != NULL
-		    && ((remsg->from_ext != NULL && atoi(remsg->from_ext) == useron.number)
-		        || stricmp(useron.alias, remsg->from) == 0 || stricmp(useron.name, remsg->from) == 0))
+		if (remsg->to != NULL) {
+		    if ((remsg->from_ext != NULL && atoi(remsg->from_ext) == useron.number)
+		        || stricmp(useron.alias, remsg->from) == 0 || stricmp(useron.name, remsg->from) == 0)
 				SAFECOPY_UTF8(touser, msghdr_field(remsg, remsg->to, NULL, term->charset() == CHARSET_UTF8));
-		else
-			SAFECOPY_UTF8(touser, from);
-		if (remsg->to != NULL)
 			strListPush(&names, remsg->to);
-		msgattr = (ushort)(remsg->hdr.attr & MSG_PRIVATE);
 			SAFECOPY(top, format_text(RegardingByToOn, remsg
 									  , title
 									  , from
 									  , msghdr_field(remsg, remsg->to, NULL, term->charset() == CHARSET_UTF8)
 									  , timestr(smb_time(remsg->hdr.when_written))
 									  , smb_zonestr(remsg->hdr.when_written.zone, NULL)));
+		}
+		msgattr = (ushort)(remsg->hdr.attr & MSG_PRIVATE);
 		if (remsg->tags != NULL)
 			SAFECOPY(tags, remsg->tags);
 	}