This is the same as bug #246966 but for JPEG XL. JPEG XL will be enabled by default project-wide, and for real for WPE and GTK ports. Still disabled in other ports for now.
(Note: this build flag controls the use of JPEG XL dependency. It won't be used by Safari or Apple platforms, which use OS-level image decoders instead.)
Pull request: https://github.com/WebKit/WebKit/pull/14790
Committed 265024@main (93865414f331): <https://commits.webkit.org/265024@main> Reviewed commits have been landed. Closing PR #14790 and removing active labels.