rootdev: Use large file support (LFS)

Without LFS, stat fails with -EOVERFLOW on devices with major:minor
numbers that don't fit within 8 bits on 32-bit architecutres. This
patch turns on LFS to allow that, fixing a bringup but on a new
platform.

BUG=chromium:464024
TEST=Booted onto a machine and successfully ran rootdev with a large
major:minor number.

Change-Id: I3dfe698e65366f4608705f56894988d2643e375f
Signed-off-by: Dan Ehrenberg <dehrenberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/258550
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>

Makefile

diff --git a/Makefile b/Makefile
index 1575f3a..5e83c57 100644
--- a/Makefile
+++ b/Makefile
@@ -1,8 +1,12 @@
-# Copyright (C) 2010 The Chromium OS Authors. All rights reserved.
+# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 CFLAGS += -Wall -Werror
+
+# Support large files and major:minor numbers
+CPPFLAGS += -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
+
 OUT = $(CURDIR)
 $(shell mkdir -p $(OUT))