How do I avoid these repetitions when using recursive make?

Suppose I开发者_JAVA技巧 have a project with two or more subfolders foo, bar, etc. I have a Makefile at the root of the project, and also in each subdirectory.

I would like to have certain targets (e.g. all, clean, etc) to run recursively in each subdirectory. My top-level Makefile looks like this:

all:
    $(MAKE) -C foo all
    $(MAKE) -C bar all

clean:
    $(MAKE) -C foo clean
    $(MAKE) -C bar clean

Seems to me there's a lot of duplication going on here. Is there a way I can avoid such tedious duplication in my Makefiles?

How about this:

SUBDIRS=foo bar
all clean:
        for dir in $(SUBDIRS) ; do \
            $(MAKE) -C $$dir $@ ; \
        done

A bit scary:

SUBDIRS=foo bar
SUBDIR_TARGETS=all clean

define subdir_rule
$(2): $(1)-$(2)
$(1)-$(2):
    make -C $(1) $(2)
endef

$(foreach targ,$(SUBDIR_TARGETS),\
    $(foreach dir,$(SUBDIRS),\
        $(eval $(call subdir_rule,$(dir),$(targ)))))

Here's how I'd do it:

SUBDIRS=foo bar baz

TARGETS = clean all whatever
.PHONY:$(TARGETS)

# There really should be a way to do this as "$(TARGETS):%:TARG=%" or something...
all: TARG=all
clean: TARG=clean
whatever: TARG=whatever

$(TARGETS): $(SUBDIRS)
    @echo $@ done

.PHONY: $(SUBDIRS)
$(SUBDIRS):
    @$(MAKE) -s -C $@ $(TARG)