As of Python 2.4, some code got added to the
bdist_wininst command to override the build_lib option
on the build command. I had successfully been using the
following command which now fails:

D:\Python24\python.exe setup.py build --force
--compiler=mingw32 --build-lib
D:\Anthony\Build\Dev\cx_Oracle\HEAD\9i-py24\win32
--build-temp
D:\Anthony\Build\Dev\cx_Oracle\HEAD\9i-py24\win32
bdist_wininst --bdist-dir
D:\Anthony\Build\Dev\cx_Oracle\HEAD\9i-py24\win32\temp
--dist-dir
D:\Anthony\Build\Dev\cx_Oracle\HEAD\9i-py24\win32

Here is the offending code from the run() method of the
bdist_wininst command:

        if self.distribution.has_ext_modules():
            # If we are building an installer for a
Python version other
            # than the one we are currently running,
then we need to ensure
            # our build_lib reflects the other Python
version rather than ours.             # Note that for
target_version!=sys.version, we must have skipped the
            # build step, so there is no issue with
enforcing the build of this
            # version.
            target_version = self.target_version
            if not target_version:
                assert self.skip_build, "Should have
already checked this"
                target_version = sys.version[0:3]
            plat_specifier = ".%s-%s" %
(get_platform(), target_version)
            build = self.get_finalized_command('build')
            build.build_lib =
os.path.join(build.build_base,
                                           'lib' +
plat_specifier)

The last line is the problem here. If I comment it out,
the problem goes away.