util/ifdtool/Makefile: Derive from Makefile.inc

Instead of maintaining two complete Makefiles, reuse the coreboot
build system rules in the stand-alone Makefile.

Change-Id: I5d894a1f079799478bce0bd200ac735097f3806b
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/59669
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/util/ifdtool/Makefile b/util/ifdtool/Makefile
index 473dc08..83d19b8 100644
--- a/util/ifdtool/Makefile
+++ b/util/ifdtool/Makefile
@@ -2,43 +2,26 @@
 #
 # SPDX-License-Identifier: GPL-2.0-only
 
-PROGRAM = ifdtool
-
 CC     ?= gcc
 INSTALL = /usr/bin/env install
 PREFIX  = /usr/local
-CFLAGS  = -O2 -g -Wall -Wextra -Wmissing-prototypes -Werror
-CFLAGS += -I../../src/commonlib/include -I../../src/commonlib/bsd/include
-CFLAGS += -I../cbfstool/flashmap
-CFLAGS += -include ../../src/commonlib/bsd/include/commonlib/bsd/compiler.h
-CFLAGS += -D_DEFAULT_SOURCE # for endianness converting functions
-LDFLAGS =
 
-OBJS = ifdtool.o
-OBJS += fmap.o
-OBJS += kv_pair.o
-OBJS += valstr.o
+HOSTCC ?= $(CC)
+HOSTCFLAGS ?= $(CFLAGS)
+top := ../..
+objutil := ..
+include Makefile.inc
 
-all: dep $(PROGRAM)
+PROGRAM=$(objutil)/ifdtool/ifdtool
 
-$(PROGRAM): $(OBJS)
-	$(CC) -o $(PROGRAM) $(OBJS) $(LDFLAGS)
+all: $(PROGRAM)
 
 clean:
 	rm -f $(PROGRAM) *.o *~ .dependencies
 distclean: clean
 
-dep:
-	@$(CC) $(CFLAGS) -MM *.c > .dependencies
-
-%.o: %.c
-	$(CC) $(CFLAGS) -c -o $@ $<
-
-%.o: ../cbfstool/flashmap/%.c
-	$(CC) $(CFLAGS) -c -o $@ $<
-
 install: $(PROGRAM)
 	mkdir -p $(DESTDIR)$(PREFIX)/bin
 	$(INSTALL) $(PROGRAM) $(DESTDIR)$(PREFIX)/bin
 
-.PHONY: all clean distclean dep
+.PHONY: all clean distclean install