On Win64, linking the python dll currently fails with 'unresolved
external symbol PyObject_Unicode'.

Building _ssl than hangs the build server because starting python.exe
displayes a message box that 'Python30.dll' cannot be found.

Temporary (?) solution: Look for existance of python30.dll and fail
the _ssl build when it is missing.
diff --git a/PCbuild/build_ssl.bat b/PCbuild/build_ssl.bat
index 9aad441..3c87f82 100644
--- a/PCbuild/build_ssl.bat
+++ b/PCbuild/build_ssl.bat
@@ -4,8 +4,10 @@
 if not defined HOST_PYTHON (

   if %1 EQU Debug (

     set HOST_PYTHON=python_d.exe

+    if not exist python30_d.dll exit 1

   ) ELSE (

     set HOST_PYTHON=python.exe

+    if not exist python30.dll exit 1

   )

 )

 %HOST_PYTHON% build_ssl.py %1 %2