From d731069286cf3ae2ee2a5cde90b16b54299d5a6f Mon Sep 17 00:00:00 2001
From: Martin Pulec <martin.pulec@cesnet.cz>
Date: Tue, 10 Feb 2026 15:20:47 +0100
Subject: [PATCH] configure.ac: set vulkan_sdl_ver

used in summary (and assumed defined) but unset if vulkan not found/enabled
---
 configure.ac | 1 +
 1 file changed, 1 insertion(+)

diff --git a/configure.ac b/configure.ac
index f8f6cc962..49de274f8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1369,6 +1369,7 @@ ENSURE_FEATURE_PRESENT([$sdl_req], [$sdl], [SDL requested but not found])
 # Vulkan
 # ------------------------------------------------------------------------------
 vulkan=no
+vulkan_sdl_ver=
 
 AC_ARG_ENABLE(vulkan,
 [  --disable-vulkan            disable sdl2_vulkan display (default is auto)]