Enable MRB_METHOD_T_STRUCT by default on 32bit GUN/Linux
Because we can't use the highest 2 bits of function pointers.
/* add -DMRB_METHOD_T_STRUCT on machines that use higher bits of pointers */
/* no MRB_METHOD_T_STRUCT requires highest 2 bits of function pointers to be zero */
#ifndef MRB_METHOD_T_STRUCT
- // can't use highest 2 bits of function pointers on 32bit Windows.
-# if defined(_WIN32) && !defined(_WIN64)
+ // can't use highest 2 bits of function pointers at least on 32bit
+ // Windows and 32bit Linux.
+# ifdef MRB_32BIT
# define MRB_METHOD_T_STRUCT
# endif
#endif
