PHP7 is deprecating PHP4 style constructors, so we need to modify our code to have _construct methods that fire before the named PHP4 style constructors. The PHP4 style constructors will call the PHP5 style constructor in case it is being called directly (usually via parent::METHOD).
This modifies external libraries to add PHP5 style constructors, but doesn't add a notice for when they are used. In WordPress core code, PHP4 style constructors are being given a call to _deprecated_constructor. To the PHP4 style constructor I say "I know that I can't take no more | It ain't no lie | I wanna see you out that door | Baby, bye, bye, bye..."
Upstream: https://wiki.php.net/rfc/remove_php4_constructors
Props jdgrimes, netweb, jorbin
See #31982
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