SDL: cmake,os2: add missing generic/SDL_syscond.c to sources

SDL Commits
1 
From b29a2827f801d1e2278c308acd447ca51ac8e057 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Thu, 1 Oct 2026 23:55:50 +0300
Subject: [PATCH] cmake,os2: add missing generic/SDL_syscond.c to sources

---
 CMakeLists.txt | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index abe54cb2dc8e4..a749a25190b71 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2829,7 +2829,8 @@ elseif(OS2)
   if(SDL_THREADS)
     set(SDL_THREAD_OS2 1)
     file(GLOB OS2_THREAD_SOURCES ${SDL2_SOURCE_DIR}/src/thread/os2/*.c)
-    list(APPEND SOURCE_FILES ${OS2_THREAD_SOURCES})
+    list(APPEND SOURCE_FILES ${OS2_THREAD_SOURCES}
+      ${SDL2_SOURCE_DIR}/src/thread/generic/SDL_syscond.c)
     set(HAVE_SDL_THREADS TRUE)
   endif()