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

include/variables.h

@@ -202,8 +202,6 @@ extern volatile OSTime gRDPTotalTime;
 
 extern ActiveSound gActiveSounds[7][MAX_CHANNELS_PER_BANK]; // total size = 0xA8
 extern u8 gSoundBankMuted[];
-extern u8 D_801333F0;
-extern u8 gAudioSfxSwapOff;
 extern u16 gAudioSfxSwapSource[10];
 extern u16 gAudioSfxSwapTarget[10];
 extern u8 gAudioSfxSwapMode[10];

include/z64.h

@@ -1453,11 +1453,11 @@ typedef struct {
     /* 0x08 */ u32       vromEnd;   // if applicable
     /* 0x0C */ void*     vramStart; // if applicable
     /* 0x10 */ void*     vramEnd;   // if applicable
-    /* 0x14 */ UNK_PTR   unk_14;
+    /* 0x14 */ void*     unk_14;
     /* 0x18 */ void*     init;    // initializes and executes the given context
     /* 0x1C */ void*     destroy; // deconstructs the context, and sets the next context to load
-    /* 0x20 */ UNK_PTR   unk_20;
-    /* 0x24 */ UNK_PTR   unk_24;
+    /* 0x20 */ void*     unk_20;
+    /* 0x24 */ void*     unk_24;
     /* 0x28 */ UNK_TYPE4 unk_28;
     /* 0x2C */ u32       instanceSize;
 } GameStateOverlay; // size = 0x30

include/z64scene.h

@@ -309,13 +309,12 @@ typedef enum {
     /* 0x6E */ SCENE_ID_MAX
 } SceneID;
 
+#undef DEFINE_SCENE
+
 // this define exists to preserve shiftability for an unused scene that is
 // listed in the entrance table
 #define SCENE_UNUSED_6E SCENE_ID_MAX
 
-#undef DEFINE_SCENE
-
-
 // Entrance Index Enum
 #define DEFINE_ENTRANCE(enum, _1, _2, _3, _4, _5, _6) enum,
 
@@ -324,6 +323,8 @@ typedef enum {
     /* 0x614 */ ENTR_MAX
 } EntranceIndex;
 
+#undef DEFINE_ENTRANCE
+
 #define ENTR_LOAD_OPENING -1
 
 typedef enum {
@@ -336,8 +337,6 @@ typedef enum {
     /* 0x7FFF */ ENTR_RETURN_GROTTO // Grottos and normal Fairy Fountain
 } ReturnEntranceIndex;
 
-#undef DEFINE_ENTRANCE
-
 typedef enum {
     /*  0 */ SDC_DEFAULT,
     /*  1 */ SDC_SPOT00,