SDL_net: Don't crash if NET_WaitUntilInputAvailable() is passed a NULL socket

SDL Commits
1 
From 65d8f55482f69c2ba5ec2897dbc1bf8ae2420a8f Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Fri, 28 Nov 2025 19:55:49 -0800
Subject: [PATCH] Don't crash if NET_WaitUntilInputAvailable() is passed a NULL
 socket

---
 src/SDL_net.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/SDL_net.c b/src/SDL_net.c
index 3bb5dea..0a4e831 100644
--- a/src/SDL_net.c
+++ b/src/SDL_net.c
@@ -1988,6 +1988,9 @@ int NET_WaitUntilInputAvailable(void **vsockets, int numsockets, int timeoutms)
     int numhandles = 0;
     for (int i = 0; i < numsockets; i++) {
         const NET_GenericSocket *sock = sockets[i];
+        if (!sock) {
+            return SDL_InvalidParamError("sockets");
+        }
         switch (sock->socktype) {
             case SOCKETTYPE_STREAM:
                 numhandles++;