There seems to be a lot of interaction of OS level and compiler used.

* Waiting for the next bot run to get a different compiler.

+++
AIX 6.1.6 and older libraries - no test errors reported

AIX 7.1.4 and newer libraries - when using the binary built on 6.1.6 (AIX 6.1 TL6) - no error

AIX 7.1.4, using xlc-v13.1.2 (try and buy version), same AIX level as the bot (7.1 TL4 SP8) - no error

Back to the bot: AIX 7.1 TL4 SP8 and gcc-4.7.4 - strange errors. See, e.g., https://buildbot.python.org/all/#/builders/302/builds/373/steps/5/logs/stdio with additional errors such as:

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests) (hx='0x1.89d8c423ea0c6p+29', hy='0x1.d35dcfe902bc3p+29', x=825956484.4892814, y=980138493.1263355)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.x.aixtools-aix-power6/build/Lib/test/test_math.py", line 867, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
AssertionError: 1281747081.1271062 != 1281747081.127106

Waiting for bot run 374 - to see if the results change when the compiler changes.

I'll try moving the bot to another system - as the system the bot is on is more than just the bot. Maybe there are side-effects coming in, unexpectedly, from other sources. ** The two systems just mentioned are fresh installs.