source and objfiles on different paths

[Riccardo Manfrin]

Hi makers,
I use to list all my $(OBJFILES)

OBJFILES+=foo/foo0.o
OBJFILES+=zoo/foo1.o
OBJFILES+=bar/foo2.o

and then mux their compiling process with rules like the following:

%.o : %.cpp
    $(COMPILE) -c  ... $< -o $@

%.o : %.c
    $(COMPILE) -c  ... $< -o $@

%.o : %.S
    $(COMPILE) -c  ... $< -o $@

My problem is that, having each objfile a peculiar path, the above rules 
generate the obj file in that same path, whereas I would like to 
generate the objfiles in a *common place* (e.g: the $(PROJROOT)/build/ 
directory)

So I need a way to "trim" the paths from the obj files or I need a 
different approach to list sources and generate objfiles from them.

It would be a real pain to have to first declare the sources and then 
append a path to each of them.

Do you have any hint on how this issue is typically handled?
Thanks in advance.
RM