crash vm trace

source/cell_internal.h

@@ -76,6 +76,10 @@ typedef struct cell_rt {
   cell_hook trace_hook;
 } cell_rt;
 
+/* Set by actor_turn/CLI before entering the VM, cleared after.
+   Read by signal_handler to print JS stack on crash. */
+extern volatile JSContext *g_crash_ctx;
+
 cell_rt *create_actor(void *wota);
 const char *register_actor(const char *id, cell_rt *actor, int mainthread, double ar);
 void actor_disrupt(cell_rt *actor);