Prefix [putref] property names with putref_.

diff --git a/tools/widl/header.c b/tools/widl/header.c
index 72e7e72..1a4cce3 100644
--- a/tools/widl/header.c
+++ b/tools/widl/header.c
@@ -105,6 +105,8 @@
     fprintf(h, "get_" );
   else if (is_attr( v->attrs, ATTR_PROPPUT ))
     fprintf(h, "put_" );
+  else if (is_attr( v->attrs, ATTR_PROPPUTREF ))
+    fprintf(h, "putref_" );
   fprintf(h, "%s", v->name);
 }