SDL: Add generic SDL_syscond to N3DS threads source list

SDL Commits
1 
From 7c12c63f63be522af2ad8e8216ea7b2786aa42a0 Mon Sep 17 00:00:00 2001
From: ds-sloth <[EMAIL REDACTED]>
Date: Tue, 28 Jan 2025 23:25:15 -0500
Subject: [PATCH] Add generic SDL_syscond to N3DS threads source list

---
 CMakeLists.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 78f36d07b8d5a..ae1c13f798b15 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2887,6 +2887,7 @@ elseif(N3DS)
   set(SDL_THREAD_N3DS 1)
   sdl_glob_sources("${SDL3_SOURCE_DIR}/src/thread/n3ds/*.c")
   sdl_sources(
+    "${SDL3_SOURCE_DIR}/src/thread/generic/SDL_syscond.c"
     "${SDL3_SOURCE_DIR}/src/thread/generic/SDL_systls.c"
     "${SDL3_SOURCE_DIR}/src/thread/generic/SDL_sysrwlock.c"
   )