Properly #if these debug hooks

...moved here with 6fbab2ce87372bd98275d8239cd782d0ca6375e8 "loplugin:unreffun";
this file still indirectly includes boost/scoped_ptr.hpp via. boost/spirit

Change-Id: Ib2f251420950395f58415c1f7c944b7e8fd61476
diff --git a/slideshow/source/engine/smilfunctionparser.cxx b/slideshow/source/engine/smilfunctionparser.cxx
index 3cc64da..2dd955f 100644
--- a/slideshow/source/engine/smilfunctionparser.cxx
+++ b/slideshow/source/engine/smilfunctionparser.cxx
@@ -626,6 +626,8 @@
     }
 }
 
+#if defined(BOOST_SP_ENABLE_DEBUG_HOOKS)
+
 // debug hooks
 
 namespace boost
@@ -641,4 +643,6 @@
 
 }
 
+#endif
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */