Land prep work to enable NaCl in the Linux x64 GN builds.

ppapi/native_client/src/untrusted/pnacl_irt_shim/BUILD.gn

+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+assert(is_nacl,
+       "These targets must only be built using the untrusted NaCl toolchains.")
+
+static_library("aot") {

[brettw, 2015/02/25 22:22:25]

source_set (also twice below)

[Dirk Pranke, 2015/02/25 23:23:40]

Done.

+  sources = [
+    "irt_shim_ppapi.c",
+    "pnacl_shim.c",
+    "shim_entry.c",
+    "shim_ppapi.c",
+  ]
+}
+
+static_library("browser") {
+  sources = [
+    "shim_entry.c",
+    "shim_ppapi.c",
+  ]
+}
+
+static_library("irt") {
+  sources = [
+    "irt_shim_ppapi.c",
+    "pnacl_shim.c",
+  ]
+}