runtime: fix build

R=golang-dev
CC=golang-dev
https://golang.org/cl/7529049

diff --git a/src/pkg/runtime/netpoll.goc b/src/pkg/runtime/netpoll.goc
index 2c61952700b6abc771502b8f95a9c422e38c4de2..84810003ea049ada723af4f9c0efcb8d4a462a1f 100644 (file)
--- a/src/pkg/runtime/netpoll.goc
+++ b/src/pkg/runtime/netpoll.goc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build darwin
+
 package net
 
 #include "runtime.h"