Re:How to adding pathes to dependencies in rules of `.d` files

My Makefile used to build source files in the subdir is like this:

```
# build shared library with -fPIC, -shared
CFLAGS   = -fPIC # -g -O3 -fPIC # CXXFLAGS for .cpp
LDFLAGS  = -shared # -L../bar -Wl,-rpath,/foo/bar # -shared
LDLIBS   = # -lbar
CPPFLAGS = -MMD -MP # -I../bar
DIR      = $(BUILD_DIR)/foo

#LDFLAGS += -Wl,-rpath,'$$ORIGIN/../foo'

$(DIR)/foo : $(addprefix $(DIR)/,$(patsubst %.c,%.o,$(wildcard *.c)))  # .cpp
#	$(CC) $(LDFLAGS) $^ $(LDLIBS) -o $@  # CXX for .cpp

$(DIR)/%.o : %.c  # .cpp
	@mkdir -p $(dir $@)
	$(CC) $(CFLAGS) $(CPPFLAGS) -c -o $@ $< # .cpp


-include $(shell find . -type f -name "*.d")
clean : ; -rm -fr $(DIR)
.PHONY : clean
```

The `.c`, `.h` files in the `.d` files are left without paths. 

```
$ cat build/foo/foo.d 
/home/ljh/Documents/make_outofsrc/src/build/foo/foo.o: foo.c foo.h
foo.h:
$
```