Index: common_types.h
===================================================================
--- common_types.h	(revision 3201)
+++ common_types.h	(revision 3202)
@@ -18,6 +18,9 @@
 typedef struct csch_sheet_s csch_sheet_t;
 typedef struct csch_cgrp_s csch_cgrp_t;
 
+/* from abstract.h */
+typedef struct csch_abstract_s csch_abstract_t;
+
 /* project/view */
 typedef struct csch_project_s csch_project_t;
 typedef struct csch_view_s csch_view_t;