As part of the early Mesa 24.3 changes for this open-source 3D graphics driver stack coming out in Q4, a new “legacy-x11” build option has been introduced to its Meson build system.
Red Hat’s Adam Jackson has added this new “legacy-x11″ build option for Mesa to begin punting out older X11 support behind this option. Mesa already allows building without X11 platform support but this new option allows for continuing to build X11 support but beginning to gut out older X11 dependents. Initially gated behind this new legacy-x11 build option is the DRI2 protocol support with DRI3 for years now taking the driver seat. Adam Jackson explained in the merge request: ”This is another attempt to excise DRI2 protocol support from the build. A new list option legacy-x11 is introduced, and the dri2 feature for it corresponds to X11 protocol support for the DRI2 extension. We no longer build that support by default, removing it incrementally from GLX, EGL, and the video frontends. The result no longer links against libxcb-dri2 or (for GLX) defines any xlib binding to DRI2.”
Red Hat’s quest for modernizing the Linux desktop continues.

See this merge if interested in more details on this new “legacy-x11” option now within Mesa 24.3-devel.