SDL_rtf: cmake: -Wl,-undefined,error should not be used on OpenBSD

SDL Commits
1 
From e1501aa08f7889f7dda2ea22400834230e11a3c9 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <[EMAIL REDACTED]>
Date: Sat, 14 Dec 2024 22:18:51 +0100
Subject: [PATCH] cmake: -Wl,-undefined,error should not be used on OpenBSD

---
 cmake/PrivateSdlFunctions.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmake/PrivateSdlFunctions.cmake b/cmake/PrivateSdlFunctions.cmake
index b30f380..1f3786c 100644
--- a/cmake/PrivateSdlFunctions.cmake
+++ b/cmake/PrivateSdlFunctions.cmake
@@ -276,7 +276,7 @@ macro(sdl_check_linker_flag flag var)
 endmacro()
 
 function(sdl_target_link_options_no_undefined TARGET)
-    if(NOT MSVC)
+    if(NOT MSVC AND NOT CMAKE_SYSTEM_NAME MATCHES ".*OpenBSD.*")
         if(CMAKE_C_COMPILER_ID MATCHES "AppleClang")
             target_link_options(${TARGET} PRIVATE "-Wl,-undefined,error")
         else()