SDL_mixer: cmake: -Wl,-undefined,error should not be used on OpenBSD (cdfea)

SDL Commits
1 
From cdfeae5d4df2ee15a266aed8305cbd3ad1d37b70 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <[EMAIL REDACTED]>
Date: Sat, 14 Dec 2024 21:42:04 +0100
Subject: [PATCH] cmake: -Wl,-undefined,error should not be used on OpenBSD

(cherry picked from commit 73a3e316728646ded6495b4dfddf1869ace43edf)
---
 cmake/PrivateSdlFunctions.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmake/PrivateSdlFunctions.cmake b/cmake/PrivateSdlFunctions.cmake
index b30f380ae..1f3786c05 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()