Issue 4863: Protect Grob_interface<>::interface_symbol_

diff --git a/lily/include/grob-interface.hh b/lily/include/grob-interface.hh
index 9c3eadb4b06b7deccf252f2cabfbe65f4cc91fa1..bde5f5263d4130091afbd44a803501ee9fc9da69 100644 (file)
--- a/lily/include/grob-interface.hh
+++ b/lily/include/grob-interface.hh
@@ -21,6 +21,7 @@
 #define INTERFACE_HH
 
 #include "lily-guile.hh"
+#include "protected-scm.hh"
 
 class Grob;
 
@@ -57,14 +58,14 @@ private:
   friend bool has_interface(Grob *);
 
 private:
-  static SCM interface_symbol_;
+  static Protected_scm interface_symbol_;
   static char const *cxx_name_;
   static char const *description_;
   static char const *variables_;
 };
 
 template <class Interface>
-SCM Grob_interface<Interface>::interface_symbol_;
+Protected_scm Grob_interface<Interface>::interface_symbol_;
 
 #endif /* INTERFACE_HH */