Make sure scalar containers are fresh per frame.

Also stub the place we'll later need to provide some support for state
variables.

src/core/frame.c

@@ -158,6 +158,31 @@ void MVM_frame_invoke(MVMThreadContext *tc, MVMStaticFrame *static_frame,
         if (fresh)
             frame->env = malloc(static_frame_body->env_size);
         memcpy(frame->env, static_frame_body->static_env, static_frame_body->env_size);
+        if (static_frame_body->static_env_flags) {
+            MVMROOT(tc, static_frame, {
+                /* Drag everything out of static_frame_body before we start,
+                 * as GC action may invalidate it. */
+                MVMuint8 *flags = static_frame_body->static_env_flags;
+                MVMint64 numlex = static_frame_body->num_lexicals;
+                MVMint64 i;
+                for (i = 0; i < numlex; i++) {
+                    switch (flags[i]) {
+                        case 0: break;
+                        case 1:
+                            frame->env[i].o = MVM_repr_clone(tc, frame->env[i].o);
+                            break;
+                        case 2:
+                            printf("WARNING: State vars NYI\n");
+                            frame->env[i].o = MVM_repr_clone(tc, frame->env[i].o);
+                            break;
+                        default:
+                            MVM_exception_throw_adhoc(tc,
+                                "Unknown lexical environment setup flag");
+                    }
+                }
+            });
+            static_frame_body = &static_frame->body; /* In case it moved. */
+        }
     }
     else {
         frame->env = NULL;