fix build with older libvirt missing virNWFilterBindingPtr

While we correctly disable all public API bindings that rely on
virNWFilterBindingPtr, the generator is still creating a helper function
that needs it - libvirt_virNWFilterBinding_pointer. Making this helper
conditional is a little hairy, so just provide a trivial typedef to keep
it happy.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

typewrappers.h

@@ -27,6 +27,10 @@
 typedef ssize_t Py_ssize_t;
 #endif
 
+#if !LIBVIR_CHECK_VERSION(4, 5, 0)
+typedef struct _virNWFilterBinding *virNWFilterBindingPtr;
+#endif
+
 #define PyvirConnect_Get(v) (((v) == Py_None) ? NULL : \
         (((PyvirConnect_Object *)(v))->obj))