Report bigger "size of message" in POP3 LIST response

For messages that have no body, we'd report 0. But RFC 1939 says this value
is supposed to be "the exact size of the message in octets" <sigh>. This
would include header fields, so while we can't know the exact RFC822 size,
adding the msg's hdr.length to these values gives size > 0 for messages
with no body text and this enables the Apple iPhone Mail app to download
the message (fixing issue #822).

Part two of this fix is to provide a blank line of message text when there
is none. This changes the message displayed in the iPhone Mail app from:

"This message cannot be displayed because of the way it is formatted.
 Ask the sender to send it again using a different format or email program.

 text/plain"

to (the much nicer):
 "This message has no content".

src/sbbs3/mailsrvr.c

@@ -874,7 +874,11 @@ static ulong sockmimetext(SOCKET socket, const char* prot, CRYPT_SESSION sess, s
 
 	/* MESSAGE BODY */
 	lines=0;
-	np=msgtxt;
+	if(*msgtxt == '\0')
+		np = "\r\n"; // Send at least one line of message text (issue #822)
+	else
+		np = msgtxt;
+	long bytes = 0;
 	while(*np && lines<maxlines) {
 		len=0;
 		while(len<RFC822_MAX_LINE_LEN && *(np+len)!=0 && *(np+len)!='\n')
@@ -886,6 +890,7 @@ static ulong sockmimetext(SOCKET socket, const char* prot, CRYPT_SESSION sess, s
 
 		if(!sockprintf(socket,prot,sess, "%s%.*s", *np=='.' ? ".":"", tlen, np))
 			break;
+		bytes += tlen;
 		lines++;
 		if(*(np+len)=='\r')
 			len++;
@@ -898,10 +903,10 @@ static ulong sockmimetext(SOCKET socket, const char* prot, CRYPT_SESSION sess, s
 			YIELD();
 		if((lines%100) == 0)
 			lprintf(LOG_DEBUG,"%04d %s sent %lu lines (%ld bytes) of body text"
-				,socket, prot, lines, (long)(np-msgtxt));
+				,socket, prot, lines, bytes);
 	}
 	lprintf(LOG_DEBUG,"%04d %s sent %lu lines (%ld bytes) of body text"
-		,socket, prot, lines, (long)(np-msgtxt));
+		,socket, prot, lines, bytes);
 	if(file_list!=NULL) {
 		for(i=0;file_list[i];i++) {
 			sockprintf(socket,prot,sess,"");
@@ -1527,7 +1532,7 @@ static bool pop3_client_thread(pop3_t* pop3)
 						continue;
 					}
 					if(!strnicmp(buf, "LIST",4)) {
-						sockprintf(socket,client.protocol,session,"+OK %" PRIu32 " %u",msgnum,smb_getmsgtxtlen(&msg));
+						sockprintf(socket,client.protocol,session,"+OK %" PRIu32 " %u",msgnum,msg.hdr.length + smb_getmsgtxtlen(&msg));
 					} else /* UIDL */
 						sockprintf(socket,client.protocol,session,"+OK %" PRIu32 " %u",msgnum,msg.hdr.number);
 
@@ -1559,7 +1564,7 @@ static bool pop3_client_thread(pop3_t* pop3)
 						break;
 					}
 					if(!strnicmp(buf, "LIST",4)) {
-						sockprintf(socket,client.protocol,session,"%u %u",l+1,smb_getmsgtxtlen(&msg));
+						sockprintf(socket,client.protocol,session,"%u %u",l+1,msg.hdr.length + smb_getmsgtxtlen(&msg));
 					} else /* UIDL */
 						sockprintf(socket,client.protocol,session,"%u %u",l+1,msg.hdr.number);
 
@@ -1634,16 +1639,16 @@ static bool pop3_client_thread(pop3_t* pop3)
 					lines=-1;
 
 				sockprintf(socket,client.protocol,session,"+OK message follows");
-				lprintf(LOG_DEBUG,"%04d %s <%s> sending message text (%lu bytes)"
-					,socket, client.protocol, user.alias, (ulong)strlen(msgtxt));
+				lprintf(LOG_DEBUG,"%04d %s <%s> sending message text (%lu bytes) from %s"
+					,socket, client.protocol, user.alias, (ulong)strlen(msgtxt), msg.from);
 				lines_sent=sockmsgtxt(socket, client.protocol, session, &msg, msgtxt, lines);
 				/* if(startup->options&MAIL_OPT_DEBUG_POP3) */
 				if(lines!=-1 && lines_sent<lines)	/* could send *more* lines */
-					lprintf(LOG_WARNING,"%04d %s <%s> !ERROR sending message text (sent %ld of %ld lines)"
-						,socket, client.protocol, user.alias, lines_sent, lines);
+					lprintf(LOG_WARNING,"%04d %s <%s> !ERROR sending message text (sent %ld of %ld lines) from %s"
+						,socket, client.protocol, user.alias, lines_sent, lines, msg.from);
 				else {
-					lprintf(LOG_DEBUG,"%04d %s <%s> message transfer complete (%lu lines)"
-						,socket, client.protocol, user.alias, lines_sent);
+					lprintf(LOG_DEBUG,"%04d %s <%s> message transfer complete (%lu lines) from %s"
+						,socket, client.protocol, user.alias, lines_sent, msg.from);
 
 					if((i=smb_locksmbhdr(&smb))!=SMB_SUCCESS) {
 						lprintf(LOG_ERR,"%04d %s <%s> !ERROR %d (%s) locking message base"