Fix typo on MRB_DISABLE_STDIO.

mrbgems/mruby-compiler/core/codegen.c

@@ -96,7 +96,7 @@ codegen_error(codegen_scope *s, const char *message)
     mrb_pool_close(s->mpool);
     s = tmp;
   }
-#ifndef MBB_DISABLE_STDIO
+#ifndef MRB_DISABLE_STDIO
   if (s->filename && s->lineno) {
     fprintf(stderr, "codegen error:%s:%d: %s\n", s->filename, s->lineno, message);
   }