The distro OCIO is too old for the bridge's API floor where it matters
(Ubuntu 24.04 ships 2.1; the bridge uses 2.4+ APIs), and version drift
across platforms is a support hazard — enable ocio-rs' bundled feature
and drop the OCIO_INSTALL_DIR/system-package wiring from CI and CD so
Linux, macOS and Windows all build the same vendored OCIO. cmake/make/
diffutils added where the runners lack them (Windows FFmpeg build needs
make + cmp).
Mike-Solar
3c31c67f99