bugfix: wrongly strict stream class check in poll.

* sysif.c (poll_wrap): Fix function not accepting streams
of type stdio-stream or any other derived stream type.
We must check that the object is subtyped from stream,
not that it's exactly of type stream.

1 files changed, 1 insertions, 1 deletions

diff --git a/sysif.c b/sysif.c
index 26b67f3a..fa88128d 100644
--- a/sysif.c
+++ b/sysif.c
@@ -790,7 +790,7 @@ static val poll_wrap(val poll_list, val timeout_in)
       pfd[i].fd = c_num(obj);
       break;
     case COBJ:
-      if (obj->co.cls == stream_s) {
+      if (subtypep(obj->co.cls, stream_s)) {
         val fdval = stream_get_prop(obj, fd_k);
         if (!fdval) {
           free(pfd);