configure vs. multi-build environments

[Troy Cauble]

Greetings,

I write a lot of Makefiles that support a codebase that builds for
a handful of targets.  Basically, every Makefile does

    make -C <build_dir> -f ../Makefile SECOND_TIME=1 $@

where <build_dir> is determined by environment variables.
Some of the "alternate" build environments are cross-compiles
for embedded targets, some are other local builds on machines
that NFS mount my working directories.

This gives me the ability build and test changes to my working
directories on multiple targets without copying a lot of
files back and forth.  Also, the object files for one environment
don't get blown away when I compile & test another.


Now, I'd like to integrate a large, third-party, configure-based
codebase into this environment.  I'd like to have the same capabilities
listed in the previous paragraph, although the mechanism can
be different.

What's the best way to achieve this?

I've used configure with cross-compile options, but I've never
seen any use-target-specific-directories options.  And then
there's the fact that Makefiles are generated...
Maybe I need to become re-aquainted with VPATH ??

Thanks for any hints,
-troy