Redefine the unused MSG_TRUNCFILE msg auxattr flag to MSG_MIMEATTACH, used to

indicate that a message's body text contains one or more MIME-encoded/embedded
attachments - so that entities won't have to parse the message headers/body
to determine whether or not a message has MIME-attachments.

src/sbbs3/atcodes.cpp

@@ -1093,7 +1093,7 @@ const char* sbbs_t::atcode(char* sp, char* str, size_t maxlen)
 		safe_snprintf(str,maxlen,"%s%s%s%s%s%s%s"
 			,current_msg->hdr.auxattr&MSG_FILEREQUEST	? "FileRequest  "   :nulstr
 			,current_msg->hdr.auxattr&MSG_FILEATTACH	? "FileAttach  "    :nulstr
-			,current_msg->hdr.auxattr&MSG_TRUNCFILE		? "TruncFile  "		:nulstr
+			,current_msg->hdr.auxattr&MSG_MIMEATTACH	? "MimeAttach  "	:nulstr
 			,current_msg->hdr.auxattr&MSG_KILLFILE		? "KillFile  "      :nulstr
 			,current_msg->hdr.auxattr&MSG_RECEIPTREQ	? "ReceiptReq  "	:nulstr
 			,current_msg->hdr.auxattr&MSG_CONFIRMREQ	? "ConfirmReq  "    :nulstr

src/smblib/smbdefs.h

@@ -277,8 +277,8 @@
 
 										/* Auxiliary header attributes */
 #define MSG_FILEREQUEST 	(1<<0)		/* File request */
-#define MSG_FILEATTACH		(1<<1)		/* File(s) attached to Msg */
-#define MSG_TRUNCFILE		(1<<2)		/* Truncate file(s) when sent */
+#define MSG_FILEATTACH		(1<<1)		/* File(s) attached to Msg (file paths/names in subject) */
+#define MSG_MIMEATTACH		(1<<2)		/* Message has one or more MIME-embedded attachments */
 #define MSG_KILLFILE		(1<<3)		/* Delete file(s) when sent */
 #define MSG_RECEIPTREQ		(1<<4)		/* Return receipt requested */
 #define MSG_CONFIRMREQ		(1<<5)		/* Confirmation receipt requested */