diff --git a/include/ichain.h b/include/ichain.h
index 37af91057e..07bd073133 100644
--- a/include/ichain.h
+++ b/include/ichain.h
@@ -1,6 +1,8 @@
 #ifndef ICHAIN_H
 #define ICHAIN_H
 
+#include "libc/stddef.h"
+
 typedef struct {
     u32 cont:   1;
     u32 type:   4;
@@ -36,7 +38,7 @@ typedef enum {
  * * cont ----- ICHAIN_CONTINUE (or ICHAIN_STOP) to continue (or stop) parsing
  */
 #define ICHAIN(type, member, value, cont)      \
-        { cont, type, OFFSETOF(Actor, member), value }
+        { cont, type, offsetof(Actor, member), value }
 
 #define ICHAIN_U8(member, val, cont)            ICHAIN(ICHAINTYPE_U8, member, val, cont)
 #define ICHAIN_S8(member, val, cont)            ICHAIN(ICHAINTYPE_S8, member, val, cont)
diff --git a/include/libc/stddef.h b/include/libc/stddef.h
index ac71ed3629..b8c9859b0f 100644
--- a/include/libc/stddef.h
+++ b/include/libc/stddef.h
@@ -7,4 +7,10 @@ typedef unsigned long size_t;
 
 typedef unsigned int uintptr_t;
 
+#ifdef __GNUC__
+#define offsetof(structure, member) __builtin_offsetof (structure, member)
+#else
+#define offsetof(structure, member) ((size_t)&(((structure*)0)->member))
+#endif
+
 #endif
diff --git a/include/macros.h b/include/macros.h
index b979dd1295..a919de4274 100644
--- a/include/macros.h
+++ b/include/macros.h
@@ -8,8 +8,6 @@
 #define VIRTUAL_TO_PHYSICAL(addr) (u32)((u8*)(addr) - 0x80000000)
 #define SEGMENTED_TO_VIRTUAL(addr) PHYSICAL_TO_VIRTUAL(gSegments[SEGMENT_NUMBER(addr)] + SEGMENT_OFFSET(addr))
 
-#define OFFSETOF(structure, member) ((size_t)&(((structure*)0)->member))
-
 #define SQ(x) ((x)*(x))
 #define ABS(x) ((x) >= 0 ? (x) : -(x))
 #define DECR(x) ((x) == 0 ? 0 : --(x))
diff --git a/src/code/z_sram.c b/src/code/z_sram.c
index 5d6b25982f..f2844a88a2 100644
--- a/src/code/z_sram.c
+++ b/src/code/z_sram.c
@@ -74,13 +74,13 @@ typedef struct {
 #define SLOT_SIZE (sizeof(SaveContext) + 0x28)
 #define CHECKSUM_SIZE (sizeof(Save) / 2)
 
-#define DEATHS OFFSETOF(SaveContext, deaths)
-#define NAME OFFSETOF(SaveContext, playerName)
-#define N64DD OFFSETOF(SaveContext, n64ddFlag)
-#define HEALTH_CAP OFFSETOF(SaveContext, healthCapacity)
-#define QUEST OFFSETOF(SaveContext, inventory.questItems)
-#define DEFENSE OFFSETOF(SaveContext, inventory.defenseHearts)
-#define HEALTH OFFSETOF(SaveContext, health)
+#define DEATHS offsetof(SaveContext, deaths)
+#define NAME offsetof(SaveContext, playerName)
+#define N64DD offsetof(SaveContext, n64ddFlag)
+#define HEALTH_CAP offsetof(SaveContext, healthCapacity)
+#define QUEST offsetof(SaveContext, inventory.questItems)
+#define DEFENSE offsetof(SaveContext, inventory.defenseHearts)
+#define HEALTH offsetof(SaveContext, health)
 
 #define SLOT_OFFSET(index) (SRAM_HEADER_SIZE + 0x10 + (index * SLOT_SIZE))
 
diff --git a/src/overlays/gamestates/ovl_file_choose/file_choose.h b/src/overlays/gamestates/ovl_file_choose/file_choose.h
index b3cc2844fa..a0e4994661 100644
--- a/src/overlays/gamestates/ovl_file_choose/file_choose.h
+++ b/src/overlays/gamestates/ovl_file_choose/file_choose.h
@@ -1,12 +1,13 @@
 #ifndef _FILE_CHOOSE_H_
 #define _FILE_CHOOSE_H_
 
+#include "libc/stddef.h"
 #include "ultra64.h"
 #include "global.h"
 #include "vt.h"
 
 
-#define GET_NEWF(sramCtx, slotNum, index) (sramCtx->readBuff[gSramSlotOffsets[slotNum] + OFFSETOF(SaveContext, newf[index])])
+#define GET_NEWF(sramCtx, slotNum, index) (sramCtx->readBuff[gSramSlotOffsets[slotNum] + offsetof(SaveContext, newf[index])])
 
 #define SLOT_OCCUPIED(sramCtx, slotNum) \
     ((GET_NEWF(sramCtx, slotNum, 0) == 'Z') || \