Add an ugly pointer-fiddling subtype() definition for ancient compilers

1 files changed, 5 insertions, 0 deletions

diff --git a/types.h b/types.h
index 232a7ce..3002c6e 100644
--- a/types.h
+++ b/types.h
@@ -13,7 +13,12 @@ typedef unsigned long long u64;
 typedef signed short s16;
 typedef signed int s32;
 
+#if 0
 #define subtype(_type, _base, _field) \
 	(void *)((u8 *)(_base) - __builtin_offsetof(_type, _field))
+#else
+#define subtype(_type, _base, _field) \
+       (void *)((u8 *)(_base) - ((u8 *)&(((_type *)0)->_field) - 0))
+#endif
 
 #endif