'exits(0)' should be 'threadexitsall(nil)'.
Reference: /n/sources/patch/applied/venti-buildindex-exits
Date: Sat May 14 15:44:51 CES 2011
Signed-off-by: djc@9grid.fr

--- /sys/src/cmd/venti/srv/buildindex.c	Sat May 14 15:43:52 2011
+++ /sys/src/cmd/venti/srv/buildindex.c	Sat May 14 15:43:49 2011
@@ -813,7 +813,7 @@
 	}
 	if (nbuf == 0) {
 		fprint(2, "%s: brand-new index, no work to do\n", argv0);
-		exits(0);
+		threadexitsall(nil);
 	}
 
 	/* size buffer to use extra memory */