obj-y := cpu.o os.o start.o state.o
# os.c is build in the system environment, so needs standard includes
-$(obj)os.o: CFLAGS := $(filter-out -nostdinc,\
- $(patsubst -I%,-idirafter%,$(CFLAGS)))
-$(obj).depend.os: CPPFLAGS := $(filter-out -nostdinc,\
- $(patsubst -I%,-idirafter%,$(CPPFLAGS)))
+# 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)