per-target VPATH

[__alex__]

Hi all,

   It seems that gmake doesn't take in account per-target VPATH variable. I 
want to write something like

MODULE = foo

$(BUILDDIR)/$(MODULE)/.obj/bar.o : VPATH = $(SRCDIR)/$(MODULE)

$(BUILDDIR)/$(MODULE)/.obj/%.o : %.cxx
        $(CXX) $(CXX_FLAGS) -c -o $@ $<

I'm playing with the idea of having non-recursive makefile(s) for 
multi-directory build. 
Without target-specific VPATH I need to either specify exact source directory 
in the rule, like:

$(BUILDDIR)/$(MODULE)/.obj/%.o : $(SRCDIR)/$(MODULE)/%.cxx
        $(CXX) $(CXX_FLAGS) -c -o $@ $<

(if a module has multiple source directories and different source file suffixes 
it's not convenient)
or have a single vpath directive for an entire build tree:

SOURCE_PATH = $(MODULE1_SRCDIR):$(MODULE2_SRCDIR):$(MODULE3_SRCDIR)

vpath %.cxx $(SOURCE_PATH)
...
$(BUILDDIR)/$(MODULE)/.obj/%.o : %.cxx
        $(CXX) $(CXX_FLAGS) -c -o $@ $<

though in this case source file name must be unique accross the whole source 
tree.
Having working pattern-specific VPATH would be even better. I wonder whether 
it's going to be 
implemented in future versions of gmake. Any ideas and suggestions about this 
issue are welcome.

Regards,
    Alex

P.S. I've been thinking about introducing a notion of components in the build 
process. 
For example, it'd be great if gmake were able to recognize global and 
component-specific variable & rule scopes. 
Right now in order to simulate that I need to prefix each component-specific 
variable by the unique 
component name which is not very much convenient.