It looks like the buildbot started to fail with the build http://buildbot.python.org/all/builders/AMD64%20Windows7%20SP1%203.x/builds/7166/

The change 37dc870175be43cdcb6920cc642a99fc10cd4bb4 of issue #25850 changed Lib/distutils/_msvccompiler.py: "Use cross-compilation by default for 64-bit Windows.". It's an interesting suspect.

http://buildbot.python.org/all/builders/AMD64%20Windows7%20SP1%203.x/builds/7214/steps/test/logs/stdio

test test_distutils failed

======================================================================
ERROR: test_record_extensions (distutils.tests.test_install.InstallTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\_msvccompiler.py", line 480, in link
    self.spawn([self.linker] + ld_args)
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\_msvccompiler.py", line 503, in spawn
    return super().spawn(cmd)
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\ccompiler.py", line 909, in spawn
    spawn(cmd, dry_run=self.dry_run)
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\spawn.py", line 38, in spawn
    _spawn_nt(cmd, search_path, dry_run=dry_run)
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\spawn.py", line 81, in _spawn_nt
    "command %r failed with exit status %d" % (cmd, rc))
distutils.errors.DistutilsExecError: command 'C:\\Program Files (x86)\\Microsoft Visual Studio 14.0\\VC\\BIN\\x86_amd64\\link.exe' failed with exit status 1101

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\tests\test_install.py", line 215, in test_record_extensions
    cmd.run()
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\command\install.py", line 539, in run
    self.run_command('build')
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\cmd.py", line 313, in run_command
    self.distribution.run_command(command)
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\dist.py", line 974, in run_command
    cmd_obj.run()
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\command\build.py", line 135, in run
    self.run_command(cmd_name)
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\cmd.py", line 313, in run_command
    self.distribution.run_command(command)
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\dist.py", line 974, in run_command
    cmd_obj.run()
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\command\build_ext.py", line 338, in run
    self.build_extensions()
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\command\build_ext.py", line 447, in build_extensions
    self._build_extensions_serial()
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\command\build_ext.py", line 472, in _build_extensions_serial
    self.build_extension(ext)
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\command\build_ext.py", line 557, in build_extension
    target_lang=language)
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\ccompiler.py", line 717, in link_shared_object
    extra_preargs, extra_postargs, build_temp, target_lang)
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\distutils\_msvccompiler.py", line 483, in link
    raise LinkError(msg)
distutils.errors.LinkError: command 'C:\\Program Files (x86)\\Microsoft Visual Studio 14.0\\VC\\BIN\\x86_amd64\\link.exe' failed with exit status 1101