Now detects if new user record number (determined by name.dat) is beyond

the valid size of the user.dat, generates an error log message, and fixes the
user number so the record can be created successfully.

src/sbbs3/newuser.cpp

@@ -412,11 +412,16 @@ void sbbs_t::newuser()
 		fclose(stream); }
 
 	j=lastuser(&cfg);		/* Check against data file */
-	if(i<=j) {			/* Overwriting existing user */
+
+	if(i>j+1) {				/* Corrupted name.dat? */
+		errormsg(WHERE,ERR_CHK,"name.dat",i);
+		i=j+1;
+	} else if(i<=j) {			/* Overwriting existing user */
 		getuserrec(&cfg,i,U_MISC,8,str);
 		misc=ahtoul(str);
 		if(!(misc&DELETED)) /* Not deleted? Set usernumber to end+1 */
-			i=j+1; }
+			i=j+1; 
+	}
 
 	useron.number=i;
 	if((i=putuserdat(&cfg,&useron))!=0) {