[36510] allowed larger menus to be created in the Edit Menu screen by JSON-encoding the entire form into a single input field. However, it did not correctly handle nested arrays.
This introduces a new `_wp_expand_nav_menu_post_data()` helper function to handle this POST data which uses `array_replace_recursive()` internally. Since the latter is only available on PHP 5.3+, we add a compatibility function to ensure PHP 5.2 support.
Props ericlewis, neverything, swissspidy.
Fixes#36590 for trunk. See #14134.
git-svn-id: https://develop.svn.wordpress.org/trunk@37748 602fd350-edb4-49c9-b593-d223f7449a82
3f050f87c3