`uint16_t` is too small for reference count; fix
Use `uint32_t` instead. Theoretically `uint32_t` can overflow as well,
but I think it is sufficient size for embeddable Ruby VM.
MODIFY
include/mruby/irep.h
include/mruby/irep.h
@@ -44,7 +44,8 @@ typedef struct mrb_irep {
uint16_t *lines;
struct mrb_irep_debug_info* debug_info;
- uint16_t ilen, plen, slen, rlen, refcnt;
+ uint16_t ilen, plen, slen, rlen;
+ uint32_t refcnt;
} mrb_irep;
#define MRB_ISEQ_NO_FREE 1

`uint16_t` is too small for reference count; fix #4093

Use `uint32_t` instead. Theoretically `uint32_t` can overflow as well,
but I think it is sufficient size for embeddable Ruby VM.