PythonQt: Fix msvc 2010/2012 build issue

See commontk/PythonQt@9c92fd212605b

// --------------
Fix "_invalid_parameter_noinfo_noreturn" link error

By ensuring that "undef" of _DEBUG macro is not done before system
includes, it fixes the issue.

This commit is based on what has been within VTK.
See https://github.com/Kitware/VTK/commit/81d4a72c1195437403f1772559c9c28978818f03

See commontk/PythonQt#9

Thanks @Neosettler and @ihnorton for testing the patch.

Reported-by: Neosettler

CMakeExternals/PythonQt.cmake

@@ -53,7 +53,7 @@ if(${add_project})
         message(FATAL_ERROR "error: Python is required to build ${PROJECT_NAME}")
       endif()
 
-      set(revision_tag 15839e05924fa300ffc976e577b50c9b56644f12)
+      set(revision_tag 9c92fd212605bb5ff4d462323763acf65d87e4a7)
       if(${proj}_REVISION_TAG)
         set(revision_tag ${${proj}_REVISION_TAG})
       endif()