Checkout, but do not yet try to build, exernal sources.

Tools/buildbot/build-amd64.bat

 @rem Used by the buildbot "compile" step.
-REM cmd /c Tools\buildbot\external.bat
+setlocal
+cmd /c Tools\buildbot\external-amd64.bat
 call "%VS71COMNTOOLS%vsvars32.bat"
 REM cmd /q/c Tools\buildbot\kill_python.bat
 devenv.com /build ReleaseAMD64 PCbuild\pcbuild.sln

Tools/buildbot/external-amd64.bat

+@rem Fetches (and builds if necessary) external dependencies
+setlocal
+
+@rem Assume we start inside the Python source directory
+cd ..
+
+@rem sqlite
+if not exist sqlite-source-3.3.4 (
+   svn export http://svn.python.org/projects/external/sqlite-source-3.3.4
+   if exist trunk\PCbuild\sqlite3.dll del trunk\PCbuild\sqlite3.dll
+)
+
+@rem bzip
+if not exist bzip2-1.0.3 svn export http://svn.python.org/projects/external/bzip2-1.0.3
+
+@rem Sleepycat db
+call "%MSSdk%\SetEnv" /XP64 /RETAIL
+if not exist db-4.4.20 svn export http://svn.python.org/projects/external/db-4.4.20
+
+@rem OpenSSL
+if not exist openssl-0.9.8a svn export http://svn.python.org/projects/external/openssl-0.9.8a
+
+@rem tcltk
+if not exist tcl8.4.12 (
+   if exist tcltk rd /s/q tcltk
+   svn export http://svn.python.org/projects/external/tcl8.4.12
+   svn export http://svn.python.org/projects/external/tk8.4.12
+)
+