Fix the warning-flagged real bugs across the codebase (#691, 1 of 3) (#725)

* menu_items: fix the real-bug-tier compiler warnings (#691 batch 1)

Six fixes, all in menu_items.c, all verified by menu playtest on macOS:

- BSWAP16(*color0++) advanced the pointer twice per pixel on little-endian
  builds (the macro evaluates its argument twice) and mixed bytes from two
  different pixels. Read first, increment separately. Note: this function
  (func_8009A9FC) currently has no callers, so the corruption was latent,
  not live.
- func_8009B9D0 fell off the end on a lookup miss, returning garbage (the
  existing code comment already suspected this). The miss path now returns
  the display list head unchanged, i.e. draws nothing.
- update_ok_menu_item read an uninitialized stack slot for unknown menu
  item types; now selects an explicit no-animation value, matching what
  the garbage read did in practice.
- pause_menu_item_box_cursor: removed the three empty 'if (x2);' matching
  artifacts. The x/y/z spin state itself is untouched.
- func_800A1FB0: initialized var_s4/var_s5 against the guarded-but-warned
  switch default.
- func_800A54EC: initialized the pause cursor position pointer against its
  unreachable mode-switch default (would have been a null-deref class bug
  if mode values ever grew).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* collision: define the G_ENDDL opcode shifts, return 0 when no tyre surface found

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* replays: cast staff-ghost pointer comparisons, return 0 for empty ghost buffer

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* update_objects: return 0 from conditional step helpers, fix TLUT pointer comparison, init train draw distances

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* render_player: remove the impossible lamp range (vanilla bug, never glowed on N64 either)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* math_util_2: return the vector, not the address of the parameter slot

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Crab: remove inner declaration shadowing the initialized objectIndex

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* editor: honor InverseMatrix failure (bool was compared against 2, always true)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Track.h: drop dead null checks on array members

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* shells: drop always-true angle and surface gates (behavior unchanged, s16 made them tautological)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* particles: make the no-return particle setters void

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* effects/stubs/skybox/main: align signatures with functions that return nothing

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* menus/save: type the pak status variable as s32, return BAD_READ on the fall-off path

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* audio: remove uninitialized-read matching artifacts, init isSound

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* code_80005FD0/code_80086E70: init dead bomb kart pointer and the no_init variable

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* port/engine UI: fix printf-style format types and non-literal format string

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* render_objects: feed the unused texture param to the uninitialized img walker

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Format the changed lines per .clang-format

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Address review: strip explanatory comments, drop vec3f pointer returns

Comments moved to the PR record; the one flagged worth keeping stays.
vec3f_set_xyz/normalize/cross_product return void now since the out
argument is the interface and nothing used the pointer.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Update actors_extended.c

* Add checkbox for 'Shells Shoot Straight' option

* Update render_player.c

* Update PortMenu.cpp

* Update render_player.c

* Update actors_extended.c

* Update render_player.c

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: MegaMech <MegaMech@users.noreply.github.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/racing/skybox_and_splitscreen.c b/src/racing/skybox_and_splitscreen.c
index dff50e117..c669f59d1 100644
--- a/src/racing/skybox_and_splitscreen.c
+++ b/src/racing/skybox_and_splitscreen.c
@@ -257,7 +257,7 @@ UNUSED void func_802A40D4(void) {
 UNUSED void func_802A40DC(void) {
 }
 
-UNUSED s32 set_viewport2(void) {
+UNUSED void set_viewport2(void) {
     gSPViewport(gDisplayListHead++, VIRTUAL_TO_PHYSICAL(&gScreenOneCtx->viewport));
     gSPClearGeometryMode(gDisplayListHead++, G_CLEAR_ALL_MODES);
     gSPSetGeometryMode(gDisplayListHead++,
@@ -623,7 +623,8 @@ void render_screens(ScreenContext* screen, s32 mode, s32 someId, s32 playerId) {
     s32 screenId = screen - gScreenContexts;
 
     if (NULL == camera) {
-        printf("[skybox_and_splitscreen.c] Skipping rendering for screen %d. This viewport has no camera\n", screen - gScreenContexts);
+        printf("[skybox_and_splitscreen.c] Skipping rendering for screen %ld. This viewport has no camera\n",
+               (long) (screen - gScreenContexts));
         return;
     }