make problem with multiple character matching (%) operator

[Crni Gorac]

Project foo has following directory hierarchy:
    foo
    |-- Makefile
    |-- ab
    |   `-- foo.a
    `-- c

File foo/ab/foo.b should be generated from
foo/ab/foo.a and then file foo/c/foo.c from
foo/ab/foo.b. Following Makefile is used:
ABDIR = ab
CDIR  = c
VPATH = $(ABDIR)

all: $(CDIR)/foo.c

$(ABDIR)/%.b: %.a
        cp $< $@

$(CDIR)/%.c: %.b
        cp $< $@

.PHONY: clean

clean:
        -rm -rf $(ABDIR)/*.b $(CDIR)/*.c

However, after launching make, following error is
reported:
  make: *** No rule to make target `c/foo.c', needed
by `all'.  Stop.

Where I am wrong? Why it is not possible for make to
accomplish two successive multiple character matching
and conclude that it should first generate .b file,
then .c file? When all files are in same directory as
Makefile, everything goes well.

Above problem is simplification of actual problem,
that appears with (as you may already supposed) Yacc
and Lex files.

Thanks.


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