Properly #if these debug hooks

...moved here with 6fbab2ce "loplugin:unreffun";
this file still indirectly includes boost/scoped_ptr.hpp via. boost/spirit

Change-Id: Ib2f251420950395f58415c1f7c944b7e8fd61476

slideshow/source/engine/smilfunctionparser.cxx

@@ -626,6 +626,8 @@ namespace slideshow
     }
 }
 
+#if defined(BOOST_SP_ENABLE_DEBUG_HOOKS)
+
 // debug hooks
 
 namespace boost
@@ -641,4 +643,6 @@ void sp_scalar_destructor_hook(void *)
 
 }
 
+#endif
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */