net: move cgo-using darwin test to separate package

It is a goal / requirement that nothing in the standard library
on darwin require cgo, and this test-only file makes net use
cgo on darwin. Move it elsewhere.

Change-Id: I6c11a8391d3913f73ce0098ba63b29adf5864f93
Reviewed-on: https://go-review.googlesource.com/c/go/+/549255
Reviewed-by: Mauri de Souza Meneguzzo <mauri870@gmail.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Russ Cox <rsc@golang.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/src/net/internal/cgotest/resstate.go b/src/net/internal/cgotest/resstate.go
new file mode 100644
index 0000000000..1b4871109e
--- /dev/null
+++ b/src/net/internal/cgotest/resstate.go
@@ -0,0 +1,21 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build cgo && darwin
+
+package cgotest
+
+/*
+#include <resolv.h>
+*/
+import "C"
+
+import (
+	"internal/syscall/unix"
+	"unsafe"
+)
+
+// This will cause a compile error when the size of
+// unix.ResState is too small.
+type _ [unsafe.Sizeof(unix.ResState{}) - unsafe.Sizeof(C.struct___res_state{})]byte