This happens on Python 3.1:

/usr/bin/ld: cannot find -lpython3.1
collect2: ld returned 1 exit status
test test_distutils failed -- Traceback (most recent call last):
  File "/srv/buildbot/buildarea/3.1.bolen-ubuntu/build/Lib/distutils/unixccompiler.py", line 254, in link
    self.spawn(linker + ld_args)
  File "/srv/buildbot/buildarea/3.1.bolen-ubuntu/build/Lib/distutils/ccompiler.py", line 909, in spawn
    spawn(cmd, dry_run=self.dry_run)
  File "/srv/buildbot/buildarea/3.1.bolen-ubuntu/build/Lib/distutils/spawn.py", line 34, in spawn
    _spawn_posix(cmd, search_path, dry_run=dry_run)
  File "/srv/buildbot/buildarea/3.1.bolen-ubuntu/build/Lib/distutils/spawn.py", line 138, in _spawn_posix
    % (cmd[0], exit_status))
distutils.errors.DistutilsExecError: command 'gcc' failed with exit status 1

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/srv/buildbot/buildarea/3.1.bolen-ubuntu/build/Lib/distutils/tests/test_build_ext.py", line 321, in test_get_outputs
    cmd.run()
  File "/srv/buildbot/buildarea/3.1.bolen-ubuntu/build/Lib/distutils/command/build_ext.py", line 347, in run
    self.build_extensions()
  File "/srv/buildbot/buildarea/3.1.bolen-ubuntu/build/Lib/distutils/command/build_ext.py", line 456, in build_extensions
    self.build_extension(ext)
  File "/srv/buildbot/buildarea/3.1.bolen-ubuntu/build/Lib/distutils/command/build_ext.py", line 543, in build_extension
    target_lang=language)
  File "/srv/buildbot/buildarea/3.1.bolen-ubuntu/build/Lib/distutils/ccompiler.py", line 719, in link_shared_object
    extra_preargs, extra_postargs, build_temp, target_lang)
  File "/srv/buildbot/buildarea/3.1.bolen-ubuntu/build/Lib/distutils/unixccompiler.py", line 256, in link
    raise LinkError(msg)
distutils.errors.LinkError: command 'gcc' failed with exit status 1

(from http://www.python.org/dev/buildbot/builders/x86%20Ubuntu%20Shared%203.1/builds/1132/steps/test/logs/stdio )

Since it is on one of the stable buildbots, it might be considered release-blocking.