1) Checkout a 3.4 tree.  Mine was at revision d244e1770f1b.
2) ./configure
3) make -j14 profile-opt
4) ./python -m test.regrtest -v test_distutils

FAIL: test_sysconfig_module (distutils.tests.test_sysconfig.SysconfigTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/.../oss/cpython/3.4/Lib/distutils/tests/test_sysconfig.py", line 131, in test_sysconfig_module
    sysconfig.get_config_var('CFLAGS'))
AssertionError: '-Wno[38 chars] -Wall -Wstrict-prototypes  -fprofile-use -fprofile-correction' != '-Wno[38 chars] -Wall -Wstrict-prototypes'

This can be traced to the built _sysconfigdata.py file which contains the command line passed CFLAGS from the build_all_use_profile target's sub-make vs the distutils.sysconfig module's Makefile parsing which finds the PY_CFLAGS value from the Makefile itself.

One of either stripping the profile-opt related flags out when generating _sysconfigdata.py or explicitly generating a good _sysconfigdata.py file outside of the sub-make's with the profiling generate or use flags seems like a good idea.  The latter is likely easier; just regenerate _sysconfigdata.py after the sub-make.