fix gc not acknowledging macros and strings

src/gc.c

@@ -99,13 +99,16 @@ V gc_collect(Gc *gc) {
       obj->tail = forward(gc, obj->tail);
       break;
     }
-    case TYPE_CLOS: {
+    case TYPE_CLOS:
+    case TYPE_MAC: {
       Cl *obj = (Cl *)(hdr + 1);
       obj->args = forward(gc, obj->args);
       obj->body = forward(gc, obj->body);
       obj->env = forward(gc, obj->env);
       break;
     }
+    case TYPE_STR:
+      break;
     case TYPE_FWD:
       fprintf(stderr, "fatal GC error: forwarding pointer in to-space\n");
       abort();

src/main.c

@@ -24,6 +24,7 @@ int main(void) {
       error_print(&interp);
     }
     gc_rootreset(&interp.gc, mark);
+    gc_collect(&interp.gc);
     nexttoken(&lex);
   }