dtmail: Resolve format-overflow issues

cde/programs/dtmail/include/DtMail/DtMailServer.hh

@@ -194,7 +194,7 @@ protected:
     char		*_shroud;	// String to shroud in debug output.
     char		 _transtag[DTMAS_TAGSIZE]; 
 					// Tag of the current transaction.
-    int			 _transnum;	// Number of the current transaction.
+    unsigned		 _transnum;	// Number of the current transaction.
     int			 _timeout;	// Timeout seconds waiting for server.
     char		*_username;
 

cde/programs/dtmail/libDtMail/Common/DtMailServer.C

@@ -67,7 +67,7 @@
 #endif
 
 #define dtmasTAGCLR()	*_transtag = '\0'; _transnum=0;
-#define dtmasTAGGEN()	(sprintf(_transtag, "a%04d", ++_transnum), _transtag)
+#define dtmasTAGGEN()	(sprintf(_transtag, "a%04u", ++_transnum), _transtag)
 #define dtmasTAGGET()	(_transtag)
 
 static jmp_buf	restart;

cde/programs/dtmail/libDtMail/RFC/RFCMIME.C

@@ -1398,7 +1398,7 @@ RFCMIME::formatBodies(DtMailEnv & error,
 		free(bp_contents);
     }
     else {
-	char *content_type = new char[100];
+	char *content_type = new char[100 + sizeof(boundary)];
 
 	sprintf(content_type, "Content-Type: multipart/mixed;boundary=%s",
 		boundary);