>>> print(_have_functions)
['HAVE_FACCESSAT', 'HAVE_FCHDIR', 'HAVE_FCHMOD', 'HAVE_FCHMODAT', 'HAVE_FCHOWN', 'HAVE_FEXECVE', 'HAVE_FDOPENDIR', 'HAVE_FPATHCONF', 'HAVE_FSTATAT', 'HAVE_FSTATVFS', 'HAVE_FTRUNCATE', 'HAVE_FUTIMES', 'HAVE_FUTIMESAT', 'HAVE_LINKAT', 'HAVE_LCHFLAGS', 'HAVE_LCHMOD', 'HAVE_LCHOWN', 'HAVE_LSTAT', 'HAVE_LUTIMES', 'HAVE_MKDIRAT', 'HAVE_MKFIFOAT', 'HAVE_MKNODAT', 'HAVE_OPENAT', 'HAVE_READLINKAT', 'HAVE_RENAMEAT', 'HAVE_SYMLINKAT', 'HAVE_UNLINKAT']

/usr/include/utime.h exists.

FWIW, when I stepped through it a few nights ago, I remember that all the code paths eventually visited the point where the mtime gets converted into a decimal:

======================================================================
FAIL: test_utime (test.test_os.StatAttributeTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/buildslave/cpython/3.x.snakebite-freebsd91-amd64/build/Lib/test/test_os.py", line 331, in test_utime
    self._test_utime(self.fname, getattr, utime, 10)
  File "/home/buildslave/cpython/3.x.snakebite-freebsd91-amd64/build/Lib/test/test_os.py", line 318, in _test_utime
    self.assertEqual(attr(st0, "st_mtime"), attr(st1, "st_mtime"))
AssertionError: 1345497270.8923829 != 1345497270.892382

However, for the other errors:
    AssertionError: 1345497270884503433 != 1345497270884503000
    AssertionError: 1345497270888847634 != 1345497270888847000
....they'd get cast back before the assertEqual test would be done.

As for this:
    1345497270.8923829 != 1345497270.892382

The trailing 9 is getting lopped off, which results in the rounding errors.