[SDL2] Refactor the PSP Render

include/SDL_hints.h

@@ -2038,6 +2038,17 @@ extern "C" {
  */
 #define SDL_HINT_PS2_DYNAMIC_VSYNC    "SDL_PS2_DYNAMIC_VSYNC"
 
+/**
+ *  \brief  A variable controlling if VSYNC is automatically disable if doesn't reach the enough FPS
+ *
+ *  This variable can be set to the following values:
+ *    "0"       - It will be using VSYNC as defined in the main flag. Default
+ *    "1"       - If VSYNC was previously enabled, then it will disable VSYNC if doesn't reach enough speed
+ *
+ *  By default SDL does not enable the automatic VSYNC
+ */
+#define SDL_HINT_PSP_DYNAMIC_VSYNC    "SDL_PSP_DYNAMIC_VSYNC"
+
 /**
  * A variable to control whether the return key on the soft keyboard should
  * hide the soft keyboard on Android and iOS.