dependencies in other folders

[Eduardo Suárez]

Hi,

I am having problems with prerequisites in other directories, so I have 
written this script to reproduce the problem:
################START HERE
mkdir test_make test_make/a test_make/b test_make/a/aa test_make/a/ab
touch test_make/a/ab/foo.c test_make/b/bar.c
cat<<EOF | tr "=" "\t" > test_make/a/aa/Makefile
%.c: ../ab/%.c
=cp \$< \$@

%.c: ../../b/%.c
=cp \$< \$@
EOF
cd test_make/a/aa
make foo.c
make bar.c
ls -la
################END HERE

So that, bar.c gets copied to the Makefile directory, while foo.c does not.

Can you reproduce my problem? Any hint?
$ make -v
GNU Make 3.81

Regards,
-Eduardo