Make more of base compile with the Native Client toolchain.

base/os_compat_nacl.cc

+// Copyright (c) 2012 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.
+
+#include "base/os_compat_nacl.h"
+
+#include <stdlib.h>
+#include <time.h>
+
+extern "C" {
+// Native Client has no timegm().
+time_t timegm(struct tm* tm) {
+  time_t ret;
+  char* tz;
+  tz = getenv("TZ");
+  setenv("TZ", "", 1);
+  tzset();
+  ret = mktime(tm);
+  if (tz)
+    setenv("TZ", tz, 1);
+  else
+    unsetenv("TZ");
+  tzset();
+  return ret;
+}
+}  // extern "C"
+