Adding a Theme Customizer Control for Posts_Per_Page

You are so very close. In your first line just replace get_option with get_theme_mod and you’re done, provided you have already added a customizer control for posts_per_page_option in the usual way.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)