diff --git a/Makefile b/Makefile
index 62f6603b..03dba07a 100755
--- a/Makefile
+++ b/Makefile
@@ -211,7 +211,7 @@ ifeq ($(shell getconf LONG_BIT), 64)
   # Ensure that gcc treats the code as 32-bit
   CC_CHECK_CFLAGS += -m32
 endif
-CC_CHECK_CFLAGS := -fsyntax-only -fsigned-char $(INCLUDE_CFLAGS) $(DEF_INC_CFLAGS) -std=gnu90 -Wall -Wextra -Wno-format-security -Wno-main -DNON_MATCHING -DAVOID_UB -D_LANGUAGE_C -DNDEBUG
+CC_CHECK_CFLAGS := -fsyntax-only -fsigned-char $(INCLUDE_CFLAGS) $(DEF_INC_CFLAGS) -std=gnu90 -Wall -Wextra -Wno-format-security -Wno-main -DNON_MATCHING -DAVOID_UB -D_LANGUAGE_C -DNDEBUG -Werror-implicit-function-declaration
 
 #Warnings to ignore
 CC_CHECK_CFLAGS += -Wno-builtin-declaration-mismatch -Wno-pointer-to-int-cast -Wno-int-to-pointer-cast
diff --git a/lib/src/mips1/al/csplayer.c b/lib/src/mips1/al/csplayer.c
index a285c817..f6b9468b 100644
--- a/lib/src/mips1/al/csplayer.c
+++ b/lib/src/mips1/al/csplayer.c
@@ -24,6 +24,7 @@ void alCSeqNextEvent(ALCSeq *seq, ALEvent *event);
 void __CSPHandleMIDIMsg(ALCSPlayer_Custom *seqp, ALEvent *event);
 ALMicroTime __CSPVoiceHandler(void *node);
 void		__CSPHandleNextSeqEvent(ALCSPlayer *seqp);
+void func_80065A80(ALSynth *arg0, PVoice *arg1, s16 arg2);
 
 /*
  * Sequence Player public functions
diff --git a/src/camera.c b/src/camera.c
index bed16b02..664aaa70 100644
--- a/src/camera.c
+++ b/src/camera.c
@@ -550,7 +550,7 @@ void set_viewport_properties(s32 viewPortIndex, s32 posX, s32 posY, s32 width, s
         gScreenViewports[viewPortIndex].flags &= ~VIEWPORT_X_CUSTOM;
     }
     if (posY != VIEWPORT_AUTO) {
-// !@bug Viewport Y writes to the X value. Luckily, all cases this function is called use VIEWPORT_AUTO,
+//!@bug Viewport Y writes to the X value. Luckily, all cases this function is called use VIEWPORT_AUTO,
 // so this bug doesn't happen in practice.
         gScreenViewports[viewPortIndex].posX = posY;
         gScreenViewports[viewPortIndex].flags |= VIEWPORT_Y_CUSTOM;
diff --git a/src/gzip.c b/src/gzip.c
index cc636423..efc3eed9 100644
--- a/src/gzip.c
+++ b/src/gzip.c
@@ -3,6 +3,7 @@
 
 #include "gzip.h"
 #include "asset_loading.h"
+#include "PR/os_libc.h"
 
 /************ .data ************/
 
diff --git a/src/memory.h b/src/memory.h
index 29e2c280..8f21e877 100644
--- a/src/memory.h
+++ b/src/memory.h
@@ -103,5 +103,6 @@ void free_memory_pool_slot(s32 poolIndex, s32 slotIndex); // Non Matching
 void *allocate_at_address_in_main_pool(s32 size, u8 *address, u32 colorTag); // Non Matching
 void free_slot_containing_address(u8 *address); // Non Matching
 s32 get_memory_colour_tag_count(s32 arg0); // Non Matching
+s32 allocate_memory_pool_slot(s32 memoryPoolIndex, s32 slotIndex, s32 size, s32 slotIsTaken, s32 newSlotIsTaken, u32 colorTag);
 
 #endif
diff --git a/src/menu.c b/src/menu.c
index 4d5c6dc1..d12d53cd 100644
--- a/src/menu.c
+++ b/src/menu.c
@@ -29,6 +29,7 @@
 #include "racer.h"
 #include "unknown_078050.h"
 #include "unknown_0255E0.h"
+#include "lib/src/mips1/al/alSynStartVoiceParams.h"
 
 /**
  * @file Contains all the code used for every menu in the game.
@@ -634,7 +635,7 @@ CharacterSelectData gCharacterSelectBytesComplete[] = {
     /*Timber*/    { { BANJO, NONE },     { NONE, NONE },     { PIPSY, TICTOC_9, TIPTUP, CONKER },  { NONE, NONE, NONE, NONE },          0x0004 },
     /*Drumstick*/ { { NONE, NONE },      { TICTOC_9, NONE }, { DIDDY, KRUNCH, NONE, NONE },        { BUMPER, BANJO, NONE, NONE },       0x0006 },
     /*T.T*/       { { DRUMSTICK, NONE }, { TIPTUP, NONE },   { TIPTUP, CONKER, NONE, NONE },       { PIPSY, TIMBER, NONE, NONE },       0x0008 }
-// !@bug T.T's down input selects Tiptup. It should be set to NONE.
+//!@bug T.T's down input selects Tiptup. It should be set to NONE.
 };
 
 s32 D_800DFFCC = 0; // Likely unused.
@@ -2852,8 +2853,6 @@ void menu_audio_options_init(void) {
 
 GLOBAL_ASM("asm/non_matchings/menu/func_80084854.s")
 
-extern void func_8000488C(s32 *soundMask); // Temporary until the proper signature is found.
-
 #ifdef NON_EQUIVALENT
 
 // Almost matching, should be functionally equivalent
@@ -8433,7 +8432,8 @@ void render_track_selection_viewport_border(ObjectModel *objMdl) {
             numTris = objMdl->batches[i + 1].facesOffset - triOffset;
             verts = &objMdl->vertices[vertOffset];
             tris = &objMdl->triangles[triOffset];
-            if (objMdl->batches[i].textureIndex == -1) { // !@bug Never true, since textureIndex is unsigned. This should've been either `== (u8)-1` or `== 0xFF`.
+            //!@bug Never true, since textureIndex is unsigned. This should've been either `== (u8)-1` or `== 0xFF`.
+            if (objMdl->batches[i].textureIndex == -1) { 
                 tex = NULL;
                 texEnabled = FALSE;
                 var_a3 = 0;
diff --git a/src/menu.h b/src/menu.h
index 7091cc9c..6e147216 100644
--- a/src/menu.h
+++ b/src/menu.h
@@ -934,6 +934,10 @@ s32 func_80095728(Gfx **gfx, MatrixS **mtx, Vertex **vtx, s32 updateRate);
 s32 func_8008F618(Gfx **dlist, MatrixS **mat);
 void func_80093D40(UNUSED s32 updateRate);
 void func_80080BC8(Gfx **);
+void func_8009963C(void);
+void func_80081C04(s32 num, s32 x, s32 y, u8 r, u8 g, u8 b, u8 a, u8 font, u8 alignment);
+void func_80080E90(Gfx **dList, s32 x, s32 y, u8 BGr, u8 BGg, u8 BGb, u8 BGa, u8 r, u8 g, u8 b, u8 a);
+void func_80084854(void);
 
 typedef enum MenuTextures {
 /* 0x00 */ TEXTURE_UNK_00,
diff --git a/src/objects.h b/src/objects.h
index 7197b7ca..76cfd55d 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -497,5 +497,8 @@ void func_80012F94(Object *);
 void render_3d_model(Object *);
 void func_800101AC(Object *, s32);
 Object *func_8001BDD4(Object *obj, s32 *cameraID);
+void func_800135B8(Object *);
+void func_8000CC7C(Vehicle, u32, s32);
+void func_8000B020(s32, s32);
 
 #endif
diff --git a/src/racer.c b/src/racer.c
index 7033dbe0..e7c12f9d 100644
--- a/src/racer.c
+++ b/src/racer.c
@@ -28,6 +28,8 @@
 #include "unknown_005740.h"
 #include "game_ui.h"
 #include "object_models.h"
+#include "unknown_003260.h"
+
 
 #define MAX_NUMBER_OF_GHOST_NODES 360
 
@@ -214,8 +216,6 @@ struct TempStruct8 **D_8011D5B0;
 s32 D_8011D5B4;
 s16 D_8011D5B8;
 
-extern void func_8000488C(u8 *soundMask);
-
 /******************************/
 
 GLOBAL_ASM("asm/non_matchings/racer/func_80042D20.s")
diff --git a/src/textures_sprites.h b/src/textures_sprites.h
index 7a914e6d..eeb4411f 100644
--- a/src/textures_sprites.h
+++ b/src/textures_sprites.h
@@ -158,5 +158,6 @@ MemoryPoolSlot *func_8007C12C(s32 arg0, s32 arg1); // Non Matching
 void func_8007AC70(void); // Non Matching
 void func_8007BF34(Gfx **dlist, s32 arg1); // Non Matching
 void func_8007BA5C(Gfx **dlist, TextureHeader *arg1, u32 flags, s32 arg3); // Non Matching
+void build_tex_display_list(TextureHeader *tex, u8 *addr);
 
 #endif
diff --git a/src/unknown_003260.h b/src/unknown_003260.h
index cd774a9f..85254abb 100644
--- a/src/unknown_003260.h
+++ b/src/unknown_003260.h
@@ -118,8 +118,7 @@ void alSndPNew(audioMgrConfig *c);
 void func_80004604(u8 *arg0, u8 arg1);
 u8 func_8000461C(u8 *arg0);
 void func_80004638(ALBank *bnk, s16 sndIndx, s32 arg2);
-//Causes issues with its type
-//void func_8000488C(u8 *soundMask);
+void func_8000488C();
 void func_800049D8(void);
 void func_800049F8(s32 soundMask, s16 type, u32 volume);
 u16 func_80004A3C(u8 arg0);
@@ -133,5 +132,6 @@ void func_80004668(ALBank *bnk, s16 sndIndx, u8, s32);
 void audioNewThread(ALSynConfig *c, OSPri p, OSSched *arg2);
 void func_800048D8(s32);
 void func_80002C00(s32, OSMesg mesg);
+void _handleEvent(unk800DC6BC *snd, ALSndpEvent *event);
 
 #endif
diff --git a/src/unknown_0255E0.h b/src/unknown_0255E0.h
index 8dadb702..0e4774fe 100644
--- a/src/unknown_0255E0.h
+++ b/src/unknown_0255E0.h
@@ -147,5 +147,9 @@ void func_8002DE30(Object*);
 void func_8002E234(Object*, s32);
 void func_80030DE0(s32 arg0, s32 arg1, s32 arg2, s32 arg3, s32 arg4, s32 arg5, s32 arg6);
 s32 func_8002BAB0(s16, f32, f32, f32*);
+void func_800249F0(u32 arg0, u32 arg1, s32 arg2, Vehicle vehicle, u32 arg4, u32 arg5, u32 arg6);
+void func_800B82B4(LevelModel *, LevelHeader *, s32);
+void func_8000C8F8(u32, u32);
+void func_80025510(s32);
 
 #endif
diff --git a/src/weather.h b/src/weather.h
index 1a75154d..ef0a28c7 100644
--- a/src/weather.h
+++ b/src/weather.h
@@ -107,5 +107,6 @@ void f32_matrix_dot(Matrix *arg0, Matrix *arg1, Matrix *arg2);
 void func_800AC21C(void);
 void func_800AC8A8(Object *);
 void func_800ACA20(Gfx**, MatrixS**, Vertex**, ObjectSegment*);
+void func_800AB4A8(s16 weatherType, s16 weatherEnable, s16 velX, s16 velY, s16 velZ, u8 intensity, u8 opacity);
 
 #endif