fix prefix path not resolving symlinks

sdl2-config.cmake.in

@@ -14,6 +14,7 @@ macro(set_and_check _var _file)
     endif()
 endmacro()
 
+get_filename_component(CMAKE_CURRENT_LIST_DIR ${CMAKE_CURRENT_LIST_DIR} REALPATH)
 get_filename_component(prefix "${CMAKE_CURRENT_LIST_DIR}/@cmake_prefix_relpath@" ABSOLUTE)
 
 set(exec_prefix "@exec_prefix@")