Refactor idlist, move all global vars to local scope

- Replace list_foreach with LIST_FOREACH macro.
- Remove `game` global variable and make it local everywhere.
- Move global vars `fld`, `nxt` and `texts` into `game` struct.
- Add `static` qualifier to engine.c's specific global vars.
- Move `sfRenderWindow window` global var to local scope

1 files changed, 4 insertions, 2 deletions

diff --git a/include/engine.h b/include/engine.h
index 4e0ee33..48342e9 100644
--- a/include/engine.h
+++ b/include/engine.h
@@ -1,2 +1,4 @@
-void transition_init(void);
-void main_loop(void);
+struct game;
+
+void transition_init(struct game *game);
+void main_loop(struct game *);