thread: Reworked SDL_CreateThread to be consistent across platforms.

Also documented missing and weird bits, rename typedefs to fit SDL standards.

src/hidapi/libusb/hidapi_thread_sdl.h

@@ -179,7 +179,7 @@ static void hidapi_thread_create(hidapi_thread_state *state, void *(*func)(void*
      */
     param->func = func;
     param->func_arg = func_arg;
-    state->thread = SDL_CreateThreadInternal(RunInputThread, "libusb", 0, param);
+    state->thread = SDL_CreateThread(RunInputThread, "libusb", param);
 }
 
 static void hidapi_thread_join(hidapi_thread_state *state)