--- lily/include/lily-proto.hh.orig	2013-10-06 15:16:08.000000000 +0000
+++ lily/include/lily-proto.hh
@@ -31,7 +31,7 @@ class Audio_item;
 class Audio_key;
 class Audio_note;
 class Audio_piano_pedal;
-class Audio_staff;
+struct Audio_staff;
 class Audio_tempo;
 class Audio_text;
 class Audio_tie;
@@ -54,10 +54,10 @@ class Change_iterator;
 class Change_translator;
 class Chord_tremolo_iterator;
 class Cluster_engraver;
-class Column_x_positions;
+struct Column_x_positions;
 class Context;
-class Context_def;
-class Context_mod;
+struct Context_def;
+struct Context_mod;
 class Context_specced_music;
 class Dispatcher;
 class Dot_column;
@@ -87,7 +87,7 @@ class Input_file_results;
 class Item;
 class Key_performer;
 class Keyword_ent;
-class Keyword_table;
+struct Keyword_table;
 class Ligature_bracket_engraver;
 class Ligature_engraver;
 class Lily_lexer;
@@ -96,7 +96,7 @@ class Lilypond_context_key;
 class Lilypond_grob_key;
 class Line_group_engraver_group;
 class Listener;
-class Lookup;
+struct Lookup;
 class Lyric_combine_music;
 class Lyric_combine_music_iterator;
 class Lyric_engraver;
@@ -115,7 +115,7 @@ class Midi_note;
 class Midi_note_event;
 class Midi_note_off;
 class Midi_piano_pedal;
-class Midi_stream;
+struct Midi_stream;
 class Midi_tempo;
 class Midi_text;
 class Midi_time_signature;
@@ -169,7 +169,7 @@ class Skyline;
 class Skyline_entry;
 class Skyline_pair;
 class Slur_configuration;
-class Slur_score_state;
+struct Slur_score_state;
 class Source_file;
 class Sources;
 class Spacing_options;