It may be a regression introduced by commit 8ded5b803705328749622256701b3f08a9d6c5ab, bpo-32030: "Add _PyCoreConfig.module_search_paths", since it's the only change of the failing build 577.

s390x RHEL 3.x5:

http://buildbot.python.org/all/#/builders/21/builds/577

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ERROR: test_no_optimize_flag (distutils.tests.test_bdist_rpm.BuildRpmTestCase)
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Traceback (most recent call last):
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z/build/Lib/distutils/tests/test_bdist_rpm.py", line 120, in test_no_optimize_flag
    cmd.run()
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z/build/Lib/distutils/command/bdist_rpm.py", line 366, in run
    self.spawn(rpm_cmd)
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z/build/Lib/distutils/cmd.py", line 365, in spawn
    spawn(cmd, search_path, dry_run=self.dry_run)
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z/build/Lib/distutils/spawn.py", line 36, in spawn
    _spawn_posix(cmd, search_path, dry_run=dry_run)
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z/build/Lib/distutils/spawn.py", line 159, in _spawn_posix
    % (cmd, exit_status))
distutils.errors.DistutilsExecError: command 'rpmbuild' failed with exit status 1

======================================================================
ERROR: test_quiet (distutils.tests.test_bdist_rpm.BuildRpmTestCase)
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Traceback (most recent call last):
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z/build/Lib/distutils/tests/test_bdist_rpm.py", line 77, in test_quiet
    cmd.run()
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z/build/Lib/distutils/command/bdist_rpm.py", line 366, in run
    self.spawn(rpm_cmd)
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z/build/Lib/distutils/cmd.py", line 365, in spawn
    spawn(cmd, search_path, dry_run=self.dry_run)
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z/build/Lib/distutils/spawn.py", line 36, in spawn
    _spawn_posix(cmd, search_path, dry_run=dry_run)
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z/build/Lib/distutils/spawn.py", line 159, in _spawn_posix
    % (cmd, exit_status))
distutils.errors.DistutilsExecError: command 'rpmbuild' failed with exit status 1