It was logged as 0.html when link_for is called with $post

fixes #190

This reverts commit b476b66007.

Note: In a previous commit, I began making inc/mod/auth.php more modular with the check_login() function. Including it does NOT check mod login by default anymore like it does on vichan. You have to call check_login(). I've finally included it in inc/functions.php. If you have any custom pages that use inc/mod/auth.php, just including functions.php is enough now.

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Also: backports 351375185e5 (early 404)

This allows pages like create.php to not include inc/mod/pages.php while still being able to use the mod auth functions (like generating salts and passwords)

Taking into account barrucadu's comments.

Works around the fact that individual board configs are not loaded when posting by making locked boards a global setting that takes an array of boards

Obviously the proper fix is to correctly load the board configs but I can't be arsed.

same for post deletion