Fix a hang when dealing with really large numbers of files

in an incremental recursion scan.

flist.c

@@ -2349,6 +2349,7 @@ struct file_list *send_file_list(int f, int argc, char *argv[])
 		flist->sorted = flist->files;
 	flist_sort_and_clean(flist, 0);
 	file_total += flist->used;
+	file_old_total += flist->used;
 
 	if (numeric_ids <= 0 && !inc_recurse)
 		send_id_list(f);

sender.c

@@ -42,6 +42,7 @@ extern int make_backups;
 extern int inplace;
 extern int batch_fd;
 extern int write_batch;
+extern int file_old_total;
 extern struct stats stats;
 extern struct file_list *cur_flist, *first_flist, *dir_flist;
 
@@ -197,8 +198,11 @@ void send_files(int f_in, int f_out)
 				end_progress(0);
 			}
 			if (inc_recurse && first_flist) {
+				file_old_total -= first_flist->used;
 				flist_free(first_flist);
 				if (first_flist) {
+					if (first_flist == cur_flist)
+						file_old_total = cur_flist->used;
 					write_ndx(f_out, NDX_DONE);
 					continue;
 				}