Add Thread drivers

CMakeLists.txt

@@ -2524,6 +2524,12 @@ elseif(PSP)
 elseif(PS2)
   list(APPEND EXTRA_CFLAGS "-DPS2")
 
+  if(SDL_THREADS)
+    set(SDL_THREAD_PS2 1)
+    file(GLOB PS2_THREAD_SOURCES ${SDL2_SOURCE_DIR}/src/thread/generic/SDL_systls.c ${SDL2_SOURCE_DIR}/src/thread/generic/SDL_sysmutex.c ${SDL2_SOURCE_DIR}/src/thread/ps2/*.c)
+    set(SOURCE_FILES ${SOURCE_FILES} ${PS2_THREAD_SOURCES})
+    set(HAVE_SDL_THREADS TRUE)
+  endif()
   if(SDL_TIMERS)
     set(SDL_TIMER_PS2 1)
     file(GLOB PS2_TIMER_SOURCES ${SDL2_SOURCE_DIR}/src/timer/ps2/*.c)