Prepare swig for building pyauto on win

swig/Lib/python/pyruntime.swg

Index: swig/Lib/python/pyruntime.swg
===================================================================
--- swig/Lib/python/pyruntime.swg	(revision 40349)
+++ swig/Lib/python/pyruntime.swg	(working copy)
@@ -1,6 +1,19 @@
 %insert(runtime) %{
 /* Python.h has to appear first */
+// Resolve conflicting use of _DEBUG across projects.
+// #defining _DEBUG causes Python.h to require pythonXX_d.lib (instead
+// of pythonXX.lib).
+// MSVC #defines _DEBUG for Debug configuration.
+// Make sure our project, which uses the latter, doesn't trigger the
+// former since we don't want to debug python itself.
+// (http://old.nabble.com/problems-with-python24_d.lib-td4760095.html#a4760095)
+#ifdef _DEBUG
+#undef _DEBUG
 #include <Python.h>
+#define _DEBUG
+#else
+#include <Python.h>
+#endif
 %}
 
 %insert(runtime) "swigrun.swg";         /* SWIG API */