the MACOSX_DEPLOYMENT_TARGET environment variable to 10.3 when calling the
loader. And we do this with "env" because distutils apparently doesn't
understand environment variable assignments before command names.
needs to run it in the Makefile).
After installing a newer framework Python the apple-installed Python can
no longer build extension modules, because they will inadvertantly be linked
against the newer framework. This script modifies lib/config/Makefile so
it will link extensions with "-undefined dynamic_lookup", which forestalls
this problem.
Will backport to 2.4 and 2.3.