crypto: add AIX operating system

This commit adds AIX operating system to crypto package for ppc64
architecture.

Updates: #25893

Change-Id: I20047ff2fef0051b8b235ec15b064c4a95c2b9c3
Reviewed-on: https://go-review.googlesource.com/c/138722
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/crypto/rand/eagain.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd linux nacl netbsd openbsd solaris
 
 package rand
 

src/crypto/rand/rand_unix.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd linux nacl netbsd openbsd plan9 solaris
+// +build aix darwin dragonfly freebsd linux nacl netbsd openbsd plan9 solaris
 
 // Unix cryptographically secure pseudorandom number
 // generator.

src/crypto/x509/root_aix.go

+// Copyright 2018 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.
+
+package x509
+
+// Possible certificate files; stop after finding one.
+var certFiles = []string{
+	"/var/ssl/certs/ca-bundle.crt",
+}

src/crypto/x509/root_unix.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris
+// +build aix dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris
 
 package x509
 
@@ -19,6 +19,7 @@ var certDirectories = []string{
 	"/usr/local/share/certs",       // FreeBSD
 	"/etc/pki/tls/certs",           // Fedora/RHEL
 	"/etc/openssl/certs",           // NetBSD
+	"/var/ssl/certs",               // AIX
 }
 
 const (