SDL: Fix WM_SYSKEYDOWN not being trapped by IME message handling

SDL Commits
1 
From 2ef005afe52dcbfe3fa3ff2c7227283100dab43e Mon Sep 17 00:00:00 2001
From: Susko3 <[EMAIL REDACTED]>
Date: Wed, 19 Nov 2025 22:20:29 +0100
Subject: [PATCH] Fix WM_SYSKEYDOWN not being trapped by IME message handling

This would cause Alt + <something> not being trapped if handled by the system IME.
---
 src/video/windows/SDL_windowskeyboard.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/video/windows/SDL_windowskeyboard.c b/src/video/windows/SDL_windowskeyboard.c
index 33aeee5d2d447..8dd68dd8b232d 100644
--- a/src/video/windows/SDL_windowskeyboard.c
+++ b/src/video/windows/SDL_windowskeyboard.c
@@ -1087,6 +1087,14 @@ bool WIN_HandleIMEMessage(HWND hwnd, UINT msg, WPARAM wParam, LPARAM *lParam, SD
             SDL_DebugIMELog("WM_KEYDOWN normal");
         }
         break;
+    case WM_SYSKEYDOWN:
+        if (wParam == VK_PROCESSKEY) {
+            SDL_DebugIMELog("WM_SYSKEYDOWN VK_PROCESSKEY");
+            trap = true;
+        } else {
+            SDL_DebugIMELog("WM_SYSKEYDOWN normal");
+        }
+        break;
     case WM_INPUTLANGCHANGE:
         SDL_DebugIMELog("WM_INPUTLANGCHANGE");
         IME_InputLangChanged(videodata);