It was inadvertently broken by
2e0cfa16dea85dd3. Many tests still fail, but
that is unrelated to that change. It's more likely that we will remove
-Uuseperlio than fix the tests.
dSAVEDERRNO;
const int fd = PerlIO_fileno(ptr);
+#ifdef USE_PERLIO
/* Find out whether the refcount is low enough for us to wait for the
child proc without blocking. */
const bool should_wait = PerlIOUnix_refcnt(fd) == 1;
+#else
+ const bool should_wait = 1;
+#endif
svp = av_fetch(PL_fdpid,fd,TRUE);
pid = (SvTYPE(*svp) == SVt_IV) ? SvIVX(*svp) : -1;