include what you use: errno.h in sandbox/

sandbox/linux/seccomp-bpf/syscall_unittest.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 "sandbox/linux/seccomp-bpf/syscall.h"
 
 #include <asm/unistd.h>
+#include <errno.h>
 #include <fcntl.h>
 #include <sys/mman.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include <vector>
 
 #include "base/posix/eintr_wrapper.h"
 #include "build/build_config.h"
@@ skipping 213 matching lines @@
 
   // Clean up
   EXPECT_EQ(0, Syscall::Call(__NR_munmap, addr2, 8192L));
   EXPECT_EQ(0, Syscall::Call(__NR_munmap, addr3, 4096L));
   EXPECT_EQ(0, IGNORE_EINTR(Syscall::Call(__NR_close, fd)));
 }
 
 }  // namespace
 
 }  // namespace sandbox