SDL: fix CheckCOCOA on modern CMake

SDL Commits
1 
From f4fc4719a5ed2efa76da32bbdcd6940b69c01422 Mon Sep 17 00:00:00 2001
From: ShuangLiu1992 <[EMAIL REDACTED]>
Date: Mon, 9 May 2022 18:35:50 +0100
Subject: [PATCH] fix CheckCOCOA on modern CMake

Modern CMake doesn't need "LANGUAGE C" for Objective-C
set_source_files_properties(${COCOA_SOURCES} PROPERTIES LANGUAGE C) should be removed fro video/cocoa/*.m as well otherwise project won't compile
see also https://github.com/libsdl-org/SDL/commit/d3cc5764c0f66872a6b87c0ffbca66c85dccbea3
---
 cmake/sdlchecks.cmake | 1 -
 1 file changed, 1 deletion(-)

diff --git a/cmake/sdlchecks.cmake b/cmake/sdlchecks.cmake
index c7b4b8887f4..de0059387e1 100644
--- a/cmake/sdlchecks.cmake
+++ b/cmake/sdlchecks.cmake
@@ -711,7 +711,6 @@ macro(CheckCOCOA)
     endif()
     if(HAVE_COCOA)
       file(GLOB COCOA_SOURCES ${SDL2_SOURCE_DIR}/src/video/cocoa/*.m)
-      set_source_files_properties(${COCOA_SOURCES} PROPERTIES LANGUAGE C)
       set(SOURCE_FILES ${SOURCE_FILES} ${COCOA_SOURCES})
       set(SDL_VIDEO_DRIVER_COCOA 1)
       set(HAVE_SDL_VIDEO TRUE)