Add declaration for _Py_PackageContext -- needed to fix importing

of shared libraries from inside packages.

Include/modsupport.h

@@ -111,6 +111,8 @@ extern PyObject *Py_InitModule4 Py_PROTO((char *, PyMethodDef *,
 	Py_InitModule4(name, methods, (char *)NULL, (PyObject *)NULL, \
 		       PYTHON_API_VERSION)
 
+extern char *_Py_PackageContext;
+
 #ifdef __cplusplus
 }
 #endif