Move the platform-dependent stuff in renderingengine.cpp to irrlicht (#13348)

src/CMakeLists.txt

@@ -285,10 +285,6 @@ if(WIN32)
 	endif()
 else()
 	# Unix probably
-	if(BUILD_CLIENT AND NOT (HAIKU OR APPLE OR ANDROID))
-		find_package(X11 REQUIRED)
-	endif()
-
 	set(PLATFORM_LIBS ${PLATFORM_LIBS} ${CMAKE_DL_LIBS})
 	if(APPLE)
 		set(PLATFORM_LIBS "-framework CoreFoundation" ${PLATFORM_LIBS})
@@ -518,7 +514,6 @@ if(BUILD_CLIENT)
 	include_directories(SYSTEM
 		${FREETYPE_INCLUDE_DIRS}
 		${SOUND_INCLUDE_DIRS}
-		${X11_INCLUDE_DIR}
 	)
 endif()
 
@@ -545,7 +540,6 @@ if(BUILD_CLIENT)
 		${ZLIB_LIBRARIES}
 		IrrlichtMt::IrrlichtMt
 		${ZSTD_LIBRARY}
-		${X11_LIBRARIES}
 		${SOUND_LIBRARIES}
 		${SQLITE3_LIBRARY}
 		${LUA_LIBRARY}