configuratble to replace dreamcast timer with unix timers

CMakeLists.txt

@@ -2695,9 +2695,22 @@ endif()
 
   if(SDL_TIMERS)
     set(SDL_TIMER_DREAMCAST 1)
-    file(GLOB DREAMCAST_TIMER_SOURCES ${SDL2_SOURCE_DIR}/src/timer/dreamcast/*.c)
-    list(APPEND SOURCE_FILES ${DREAMCAST_TIMER_SOURCES})
-    set(HAVE_SDL_TIMERS TRUE)
+    if(SDL_TIMER_UNIX)
+      set(SDL_TIMER_UNIX 1)
+      file(GLOB TIMER_SOURCES ${SDL2_SOURCE_DIR}/src/timer/unix/*.c)
+      list(APPEND SOURCE_FILES ${TIMER_SOURCES})
+      set(SDL_TIMER_DREAMCAST 0)
+      set(HAVE_SDL_TIMERS TRUE)
+
+      if(SDL_CLOCK_GETTIME)
+        set(HAVE_CLOCK_GETTIME 1)
+      endif()   
+    endif() 
+      if(SDL_TIMER_DREAMCAST)
+        file(GLOB DREAMCAST_TIMER_SOURCES ${SDL2_SOURCE_DIR}/src/timer/dreamcast/*.c)
+        list(APPEND SOURCE_FILES ${DREAMCAST_TIMER_SOURCES})
+        set(HAVE_SDL_TIMERS TRUE)
+      endif() 
   endif()
 
   if(SDL_SENSOR)

include/SDL_config_dreamcast.h

@@ -31,7 +31,8 @@
 #define SDL_PTHREADS 1
 
 /* Enable the DREAMCAST timer support (src/timer/dreamcast/\*.c) */
-#define SDL_TIMER_DREAMCAST  1
+#define SDL_TIMER_DREAMCAST 0
+#define SDL_TIMER_UNIX 1
 
 /* Enable the DREAMCAST video driver (src/video/dreamcast/\*.c) */
 #define SDL_VIDEO_DRIVER_DREAMCAST 1