building an obj file multiple places

[Kolarik, Tony]

I've probably asked this question enough times myself for it to deserve a
place in the FAQ, but I've wiped out my personal cons "archive", so here I
go again...

I need to build a couple of files from other directories into the current
directory, as well as the directories they exist in.

# blah conscript: compile these all into this directory.
foo.c
..\foo\bar.c
..\baz\that.c

# foo conscript
bar.c

# baz conscript
that.c


I'd rather not link whole source directories to fake ones so I tried just
linking the file instead:

$file = SourcePath "$BUILD/foo/bar.c";
Link $file  => 'bar.c';

but I get: 

cons: error in file "blah\blah\Conscript" (Can't locate object method "base"
via package "dir" at cons line 950.)

Is there an easy, single conscript solution for this?
 -- Tony K.