Breaking: #102113 - Removed legacy setting 'GFX/gdlib'

See forge#102113

Description

'GFX/gdlib' is a setting that enables or disables image manipulation using GDLib, functionality used in GIFBUILDER, depending if the host system did not provide GDLib functionality.

With this change, the configuration value 'GFX/gdlib' has been removed, and TYPO3 will simply check for the GdImage PHP class being available to determine if it can be used.

Impact

TYPO3 now always enables GDLib functionality as soon as relevant GDLib classes are found.

Migration

The configuration value has been removed without replacement.

Custom code that relied on $GLOBALS['TYPO3_CONF_VARS']['GFX']['gdlib'] should instead adopt the simpler check if (class_exists(\GdImage::class)).