Add sdl3_power.odin

vendor/sdl3/sdl3_power.odin

@@ -0,0 +1,17 @@
+package sdl3
+
+import "core:c"
+
+PowerState :: enum c.int {
+	ERROR = -1,   /**< error determining power status */
+	UNKNOWN,      /**< cannot determine power status */
+	ON_BATTERY,   /**< Not plugged in, running on the battery */
+	NO_BATTERY,   /**< Plugged in, no battery available */
+	CHARGING,     /**< Plugged in, charging battery */
+	CHARGED,      /**< Plugged in, battery charged */
+}
+
+@(default_calling_convention="c", link_prefix="SDL_")
+foreign lib {
+	GetPowerInfo :: proc(seconds: ^c.int, percent: ^c.int) -> PowerState ---
+}