Turns out the off_t macro isn't used anymore, so got rid of it.

tim-one · tim-one · commit df4d1377ed10 · 2002-03-30T07:07:24.000Z
diff --git a/Objects/obmalloc.c b/Objects/obmalloc.c
@@ -222,9 +222,6 @@
 #undef  ulong
 #define ulong			unsigned long	/* assuming >= 32 bits */
 
-#undef  off_t
-#define off_t 			uint	/* 16 bits <= off_t <= 64 bits */
-
 #undef uptr
 #define uptr			Py_uintptr_t
 
