-/* from categories.c */
-void TRACE_category_alloc(void);
-void TRACE_category_release(void);
-void TRACE_category_set(smx_process_t proc, const char *category);
-char *TRACE_category_get(smx_process_t proc);
-void TRACE_category_unset(smx_process_t proc);
-void TRACE_msg_category_set(smx_process_t proc, m_task_t task);
-