Suppress warning

src/dump.c

@@ -81,7 +81,6 @@ static ptrdiff_t
 write_iseq_block(mrb_state *mrb, mrb_irep *irep, uint8_t *buf, uint8_t flags)
 {
   uint8_t *cur = buf;
-  int iseq_no;
 
   cur += uint32_to_bin(irep->ilen, cur); /* number of opcode */
   cur += write_padding(cur);