exit gracefully on error
diff --git a/src/cmd/acme/util.c b/src/cmd/acme/util.c
index c224cce..432950e 100644
--- a/src/cmd/acme/util.c
+++ b/src/cmd/acme/util.c
@@ -71,7 +71,7 @@
 error(char *s)
 {
 	fprint(2, "acme: %s: %r\n", s);
-	abort();
+	threadexitsall(nil);
 }
 
 Window*