diff --git a/public/datamap.h b/public/datamap.h
index 282d4f19..c8e024a5 100644
--- a/public/datamap.h
+++ b/public/datamap.h
@@ -110,10 +110,6 @@ DECLARE_FIELD_SIZE( FIELD_MODELINDEX,	sizeof(int) )
 DECLARE_FIELD_SIZE( FIELD_MATERIALINDEX,	sizeof(int) )
 
 
-#ifndef offsetof
-#define offsetof(s,m)	(size_t)&(((s *)0)->m)
-#endif
-
 #define ARRAYSIZE2D(p)		(sizeof(p)/sizeof(p[0][0]))
 
 #define _FIELD(name,fieldtype,count,flags,mapname,tolerance)		{ fieldtype, #name, { offsetof(classNameTypedef, name), 0 }, count, flags, mapname, NULL, NULL, NULL, sizeof( ((classNameTypedef *)0)->name ), NULL, 0, tolerance }
diff --git a/public/studio.h b/public/studio.h
index 37d6cf31..c24da1ba 100644
--- a/public/studio.h
+++ b/public/studio.h
@@ -23,9 +23,6 @@
 #include "utlvector.h"
 
 
-#ifndef offsetof
-#define offsetof(s,m)	(size_t)&(((s *)0)->m)
-#endif
 
 
 //-----------------------------------------------------------------------------
diff --git a/public/tier0/platform.h b/public/tier0/platform.h
index b72a30de..1e5624fc 100644
--- a/public/tier0/platform.h
+++ b/public/tier0/platform.h
@@ -223,6 +223,16 @@ typedef void * HINSTANCE;
 #define MAX_PATH  260
 #endif
 
+
+#ifdef GNUC
+#undef offsetof
+//#define offsetof( type, var ) __builtin_offsetof( type, var ) 
+#define offsetof(s,m)	(size_t)&(((s *)0)->m)
+#else
+#undef offsetof
+#define offsetof(s,m)	(size_t)&(((s *)0)->m)
+#endif
+
 // Used to step into the debugger
 #ifdef _WIN32
 #define DebuggerBreak()  __asm { int 3 }
diff --git a/public/vgui_controls/MessageMap.h b/public/vgui_controls/MessageMap.h
index ed768a96..677bddb9 100644
--- a/public/vgui_controls/MessageMap.h
+++ b/public/vgui_controls/MessageMap.h
@@ -22,10 +22,6 @@ namespace vgui
 
 ////////////// MESSAGEMAP DEFINITIONS //////////////
 
-#ifndef offsetof
-#define offsetof(s,m)	(size_t)&(((s *)0)->m)
-#endif
-
 #ifndef ARRAYSIZE
 #define ARRAYSIZE(p)	(sizeof(p)/sizeof(p[0]))
 #endif