Example of failure:
http://buildbot.python.org/all/builders/AMD64%20Windows7%20SP1%203.x/builds/1956/


--

Compilation log:

Project "C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\pcbuild.sln" (1) is building "C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\_ssl.vcxproj" (17) on node 1 (default targets).
Project "C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\_ssl.vcxproj" (17) is building "C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\ssl.vcxproj" (18) on node 1 (default targets).
Build:
  cd "C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\"
  "C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\amd64\python_d.exe" build_ssl.py Release x64 -a
  
  Can not find a suitable PERL:
   NO perl interpreters were found on this machine at all!
   Please install ActivePerl and ensure it appears on your path
  No Perl installation was found. Existing Makefiles are used.
  Perl is required to build the makefiles!
C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.MakeFile.Targets(38,5): error MSB3073: The command "cd "C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\" [C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\ssl.vcxproj]
C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.MakeFile.Targets(38,5): error MSB3073: "C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\amd64\python_d.exe" build_ssl.py Release x64 -a [C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\ssl.vcxproj]
C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Microsoft.MakeFile.Targets(38,5): error MSB3073: " exited with code 1. [C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\ssl.vcxproj]
Done Building Project "C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\ssl.vcxproj" (default targets) -- FAILED.
Done Building Project "C:\buildbot.python.org\3.x.kloth-win64\build\PCbuild\_ssl.vcxproj" (default targets) -- FAILED.

The build of OpenSSL was failing due to an incomplete external check-in of OpenSSL (missing the cached assembler files).

Martin has since updated the external and I have refreshed the OpenSSL exports on the buildbot.  It is no longer failing to compile, but other errors still remain.

This issue can be closed.

Thanks for the heads-up. Closing.