input: avoid heap-allocation in vlc_poll_i11e() in most cases

src/misc/interrupt.c

@@ -328,6 +328,14 @@ int vlc_poll_i11e(struct pollfd *fds, unsigned nfds, int timeout)
 
     int ret;
 
+    if (likely(nfds < 255))
+    {   /* Fast path with stack allocation */
+        struct pollfd ufd[nfds + 1];
+
+        ret = vlc_poll_i11e_inner(fds, nfds, timeout, ctx, ufd);
+    }
+    else
+    {   /* Slow path but poll() is slow with large nfds anyway. */
         struct pollfd *ufd = malloc((nfds + 1) * sizeof (*ufd));
         if (unlikely(ufd == NULL))
             return -1; /* ENOMEM */
@@ -336,6 +344,7 @@ int vlc_poll_i11e(struct pollfd *fds, unsigned nfds, int timeout)
         ret = vlc_poll_i11e_inner(fds, nfds, timeout, ctx, ufd);
         vlc_cleanup_pop();
         free(ufd);
+    }
     return ret;
 }