Allow options to specify intervals

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/parse.h b/parse.h
index b3d8613..e1b9311 100644
--- a/parse.h
+++ b/parse.h
@@ -51,6 +51,7 @@
 	int minval;
 	double maxfp;			/* max and min floating value */
 	double minfp;
+	unsigned int interval;		/* client hint for suitable interval */
 	unsigned int maxlen;		/* max length */
 	int neg;			/* negate value stored */
 	int prio;