It looks like this change may have broken some parts of distutils.  For
example, Twisted's setup.py now produces this output when running the
build_ext command:

$ ~/Projects/python/trunk/python setup.py build_ext
running build_ext
Traceback (most recent call last):
  File "setup.py", line 97, in <module>
    main(sys.argv[1:])
  File "setup.py", line 92, in main
    setup(**setup_args)
  File "./twisted/python/dist.py", line 47, in setup
    return core.setup(**get_setup_args(**kw))
  File "/home/exarkun/Projects/python/trunk/Lib/distutils/core.py", line
149, in setup
    dist.run_commands()
  File "/home/exarkun/Projects/python/trunk/Lib/distutils/dist.py", line
926, in run_commands
    self.run_command(cmd)
  File "/home/exarkun/Projects/python/trunk/Lib/distutils/dist.py", line
945, in run_command
    cmd_obj.run()
  File
"/home/exarkun/Projects/python/trunk/Lib/distutils/command/build_ext.py", line
380, in run
    self.build_extensions()
  File "./twisted/python/dist.py", line 327, in build_extensions
    self.prepare_extensions()
  File "./twisted/python/dist.py", line 318, in prepare_extensions
    if x.condition(self)]
  File "twisted/runner/topfiles/setup.py", line 14, in <lambda>
    condition=lambda builder: builder._check_header("rpc/rpc.h")),
  File "./twisted/python/dist.py", line 359, in _check_header
    self.compiler.announce("checking for %s ..." % header_name, 0)
AttributeError: 'NoneType' object has no attribute 'announce'

And PyCrypto produces this output:

running build_ext
Traceback (most recent call last):
  File "setup.py", line 163, in <module>
    core.setup(**kw)
  File "/tmp/python-buildbot/local/lib/python2.7/distutils/core.py",
line 149, in setup
    dist.run_commands()
  File "/tmp/python-buildbot/local/lib/python2.7/distutils/dist.py",
line 926, in run_commands
    self.run_command(cmd)
  File "/tmp/python-buildbot/local/lib/python2.7/distutils/dist.py",
line 945, in run_command
    cmd_obj.run()
  File
"/tmp/python-buildbot/local/lib/python2.7/distutils/command/install.py",
line 580, in run
    self.run_command('build')
  File "/tmp/python-buildbot/local/lib/python2.7/distutils/cmd.py", line
326, in run_command
    self.distribution.run_command(command)
  File "/tmp/python-buildbot/local/lib/python2.7/distutils/dist.py",
line 945, in run_command
    cmd_obj.run()
  File
"/tmp/python-buildbot/local/lib/python2.7/distutils/command/build.py",
line 132, in run
    self.run_command(cmd_name)
  File "/tmp/python-buildbot/local/lib/python2.7/distutils/cmd.py", line
326, in run_command
    self.distribution.run_command(command)
  File "/tmp/python-buildbot/local/lib/python2.7/distutils/dist.py",
line 945, in run_command
    cmd_obj.run()
  File
"/tmp/python-buildbot/local/lib/python2.7/distutils/command/build_ext.py",
line 380, in run
    self.build_extensions()
  File "setup.py", line 115, in build_extensions
    self.detect_modules()
  File "setup.py", line 119, in detect_modules
    lib_dirs = self.compiler.library_dirs + ['/lib', '/usr/lib']
AttributeError: 'NoneType' object has no attribute 'library_dirs'