Implement -used.

This doesn't agree with find's output, but I think find is buggy here.
For example, find -used +0 is returning fewer results than find -used 1,
which makes no sense given that 1 is greater than 0.

1 files changed, 2 insertions, 0 deletions

diff --git a/parse.c b/parse.c
index 2fc4fd8..154d566 100644
--- a/parse.c
+++ b/parse.c
@@ -1065,6 +1065,8 @@ static struct expr *parse_literal(struct parser_state *state) {
 	case  'u':
 		if (strcmp(arg, "-uid") == 0) {
 			return parse_test_icmp(state, eval_uid);
+		} else if (strcmp(arg, "-used") == 0) {
+			return parse_test_icmp(state, eval_used);
 		} else if (strcmp(arg, "-user") == 0) {
 			return parse_user(state);
 		}