Add poc files

commons/deprecated/backtrace.ml

@@ -0,0 +1,39 @@
+open Common
+
+(* 
+ * src: Jane Street Core library.
+ * update: Normally no more needed in OCaml 3.11 as part of the 
+ *  default runtime.
+ *)
+external print : unit -> unit = "print_exception_backtrace_stub" "noalloc"
+
+
+(* ---------------------------------------------------------------------- *)
+(* testing *)
+(* ---------------------------------------------------------------------- *)
+
+exception MyNot_Found
+
+let foo1 () =
+  if 1=1 
+  then raise MyNot_Found
+  else 2
+
+let foo2 () =
+  foo1 () + 2
+
+let test_backtrace () =
+  (try ignore(foo2 ())
+  with exn -> 
+    pr2 (Common.exn_to_s exn);
+    print();
+    failwith "other exn"
+  );
+  print_string "ok cool\n";
+  ()
+
+let actions () = 
+  [
+  "-test_backtrace", "   ",
+  Common.mk_action_0_arg test_backtrace;
+  ]