Can't build qt6 due to failed ozone platform assertion

When trying to build qt6, I get this error at the webengine stage:

CMake Error at /home/liam/repos/qt5/qtwebengine/cmake/Gn.cmake:80 (message):
  

  – GN FAILED

  ERROR at //ui/gfx/linux/BUILD.gn:8:1: Assertion failed.

  assert(ozone_platform_drm || ozone_platform_wayland || ozone_platform_x11)

  ^-----

  See //media/gpu/vaapi/BUILD.gn:211:5: which caused the file to be included.

      "//ui/gfx/linux:drm",
      ^-------------------

  1