Protect Grob_interface<>::interface_symbol_ (issue 299170043 by address@hidden)

[dak]

Reviewers: ,

Message:
Well, after lots of code analysis, I'm less sure about this making a
crucial difference (except for saving lots of code analysis which is
worthwhile in itself).

Description:
Protect Grob_interface<>::interface_symbol_

I suspect this to be the culprit for our recent patchy/stability
problem.

Please review this at https://codereview.appspot.com/299170043/

Affected files (+3, -2 lines):
  M lily/include/grob-interface.hh


Index: lily/include/grob-interface.hh
diff --git a/lily/include/grob-interface.hh b/lily/include/grob-interface.hh
index  
9c3eadb4b06b7deccf252f2cabfbe65f4cc91fa1..bde5f5263d4130091afbd44a803501ee9fc9da69  
100644
--- 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 */