replicate by: open acme on a file of length 8215 bytes, position
the cursor at the end, and right-click-search for a string
that isn't in the file... and it'll go into an infinite
loop. it happens whenever the buffer read is exactly one short of
the end of the file.

i think this bug has probably been around from day 1,
which is interesting, because it's not *that* improbable an event...

Reference: /n/sources/patch/applied/acme-search-hangup
Date: Wed Nov 21 17:15:59 CET 2007
Signed-off-by: rogpeppe@gmail.com

--- /sys/src/cmd/acme/look.c	Wed Nov 21 11:58:51 2007
+++ /sys/src/cmd/acme/look.c	Wed Nov 21 11:58:48 2007
@@ -299,11 +299,11 @@
 			fbuffree(s);
 			return TRUE;
 		}
-		if(around && q>=ct->q1)
-			break;
 		--nb;
 		b++;
 		q++;
+		if(around && q>=ct->q1)
+			break;
 	}
 	fbuffree(s);
 	return FALSE;