--- /dev/null
+#
+# Copyright (c) 2011 The Chromium OS Authors.
+#
+# (C) Copyright 2000-2003
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+#
+# SPDX-License-Identifier: GPL-2.0+
+#
+
+obj-y := cpu.o os.o start.o state.o
+obj-$(CONFIG_SANDBOX_SDL) += sdl.o
+
+# os.c is build in the system environment, so needs standard includes
+# CFLAGS_REMOVE_os.o cannot be used to drop header include path
+quiet_cmd_cc_os.o = CC $(quiet_modtag) $@
+cmd_cc_os.o = $(CC) $(filter-out -nostdinc, \
+ $(patsubst -I%,-idirafter%,$(c_flags))) -c -o $@ $<
+
+$(obj)/os.o: $(src)/os.c FORCE
+ $(call if_changed_dep,cc_os.o)
+$(obj)/sdl.o: $(src)/sdl.c FORCE
+ $(call if_changed_dep,cc_os.o)