[release-branch.go1.16] syscall: add explicit ios build tag

This permits analysis of the syscall package by tools built with
older versions of Go that do not recognize ios as a GOOS.

For #44459
Fixes #44462

Change-Id: I79cec2ffe0dbcbc2dc45a385e556dc9e62033125
Reviewed-on: https://go-review.googlesource.com/c/go/+/294634
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
(cherry picked from commit 03d36d8198428a6970ba01f5de41c264acbff8fc)
Reviewed-on: https://go-review.googlesource.com/c/go/+/294635
Reviewed-by: Cherry Zhang <cherryyz@google.com>

diff --git a/src/syscall/ptrace_ios.go b/src/syscall/ptrace_ios.go
index 2f61a88a089cefe53f707b312a4feaf2b11fb856..5209d1e0dd16057e3c3e84b1987f078fc42a63b3 100644 (file)
--- a/src/syscall/ptrace_ios.go
+++ b/src/syscall/ptrace_ios.go
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build ios
+// +build ios
+
 package syscall
 
 // Nosplit because it is called from forkAndExecInChild.