Don't use select on Windows

Windows "select" only works for sockets so don't use it to wait for async.

Reviewed-by: Rich Salz <rsalz@openssl.org>
diff --git a/apps/apps.c b/apps/apps.c
index 6d8c489..8cf3b59 100644
--- a/apps/apps.c
+++ b/apps/apps.c
@@ -2621,6 +2621,8 @@
 
 void wait_for_async(SSL *s)
 {
+    /* On Windows select only works for sockets, so we simply don't wait  */
+#ifndef OPENSSL_SYS_WINDOWS
     int width = 0;
     fd_set asyncfds;
     OSSL_ASYNC_FD *fds;
@@ -2644,4 +2646,5 @@
         fds++;
     }
     select(width, (void *)&asyncfds, NULL, NULL, NULL);
+#endif
 }