More minor isolated fixes (#1258)

* Fix reversed array access in z_boss_dodongo.c

* Remove useless return in z_en_encount2.c

* Remove some redundant externs or declarations

* Move some undefs to be performed as early as possible

* AudioOcarina_ResetStaffs -> AudioOcarina_ResetStaves

The plural appears to be staves for the music term

* Remove some uses of UNK_PTR

* Use NULL for pointers set to 0 in z_game_dlftbls.c

* Remove useless !! in z_en_tk.c

* Revert "AudioOcarina_ResetStaffs -> AudioOcarina_ResetStaves"

This reverts commit 1b7fe62408.

* Remove more redundant externs from PR suggestion

src/overlays/actors/ovl_Boss_Dodongo/z_boss_dodongo.c

@@ -55,7 +55,7 @@ static InitChainEntry sInitChain[] = {
 };
 
 void func_808C1190(s16* arg0, u8* arg1, s16 arg2) {
-    if (arg2[arg1] != 0) {
+    if (arg1[arg2] != 0) {
         arg0[arg2 / 2] = 0;
     }
 }

src/overlays/actors/ovl_En_Encount2/z_en_encount2.c

@@ -111,7 +111,6 @@ void EnEncount2_Wait(EnEncount2* this, PlayState* play) {
             }
             break;
     }
-    return;
 }
 
 void EnEncount2_SpawnRocks(EnEncount2* this, PlayState* play) {

src/overlays/actors/ovl_En_Horse/z_en_horse.c

@@ -3106,10 +3106,6 @@ void EnHorse_BgCheckSlowMoving(EnHorse* this, PlayState* play) {
     }
 }
 
-void EnHorse_HighJumpInit(EnHorse* this, PlayState* play);
-void EnHorse_Stub2(EnHorse* this);
-void EnHorse_Stub1(EnHorse* this);
-
 void EnHorse_UpdateBgCheckInfo(EnHorse* this, PlayState* play) {
     s32 pad;
     s32 pad2;

src/overlays/actors/ovl_En_Hy/z_en_hy.c

@@ -1095,7 +1095,7 @@ s32 EnHy_OverrideLimbDraw(PlayState* play, s32 limbIndex, Gfx** dList, Vec3f* po
     s32 pad;
     Vec3s sp48;
     u8 i;
-    UNK_PTR ptr;
+    void* ptr;
 
     if (1) {}
 

src/overlays/actors/ovl_En_Skj/z_en_skj.c

@@ -56,7 +56,6 @@ void EnSkj_GiveOcarinaGameReward(EnSkj* this, PlayState* play);
 void EnSkj_FinishOcarinaGameRound(EnSkj* this, PlayState* play);
 void EnSkj_WaitForNextRound(EnSkj* this, PlayState* play);
 void EnSkj_WaitForOfferResponse(EnSkj* this, PlayState* play);
-void EnSkj_SetupWaitForOcarina(EnSkj* this, PlayState* play);
 void EnSkj_CleanupOcarinaGame(EnSkj* this, PlayState* play);
 
 void EnSkj_Fade(EnSkj* this, PlayState* play);

src/overlays/actors/ovl_En_Tk/z_en_tk.c

@@ -491,7 +491,7 @@ void EnTk_Init(Actor* thisx, PlayState* play) {
 
     CollisionCheck_SetInfo2(&this->actor.colChkInfo, NULL, &sColChkInfoInit);
 
-    if (gSaveContext.dayTime <= CLOCK_TIME(18, 0) || gSaveContext.dayTime >= CLOCK_TIME(21, 0) || !!LINK_IS_ADULT ||
+    if (gSaveContext.dayTime <= CLOCK_TIME(18, 0) || gSaveContext.dayTime >= CLOCK_TIME(21, 0) || LINK_IS_ADULT ||
         play->sceneNum != SCENE_SPOT02) {
         Actor_Kill(&this->actor);
         return;

src/overlays/actors/ovl_Object_Kankyo/z_object_kankyo.c

@@ -33,8 +33,6 @@ void ObjectKankyo_DrawLightning(ObjectKankyo* this, PlayState* play);
 void ObjectKankyo_DrawSunGraveSpark(ObjectKankyo* this, PlayState* play);
 void ObjectKankyo_DrawBeams(ObjectKankyo* this, PlayState* play);
 
-extern Mtx D_01000000;
-
 static void* sEffLightningTextures[] = {
     gEffLightning1Tex, gEffLightning2Tex, gEffLightning3Tex, gEffLightning4Tex,
     gEffLightning5Tex, gEffLightning6Tex, gEffLightning7Tex, gEffLightning8Tex,