net: only "build" empty.s in non-cgo mode

In cgo mode it gets passed to gcc, and on ARM
it appears that gcc does not support // comments.

TBR=iant
CC=golang-codereviews
https://golang.org/cl/142640043

diff --git a/src/net/empty.s b/src/net/empty.s
index a515c2fe29793e5856a2444db1b16dcefca509f2..f0b255a0cff182f18de6db4dd47dff7ef3103cf1 100644 (file)
--- a/src/net/empty.s
+++ b/src/net/empty.s
@@ -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 !cgo
+
 // This file is required to prevent compiler errors
 // when the package built with CGO_ENABLED=0.
 // Otherwise the compiler says: