graphics/cairo 1.16.0 has a dependency on graphics/mesa-libs 19.0.8 which has a dependency on Python 2.7 . Python 2.7 has already reached End of Life upstream. Consequently, the mesa-libs port has been marked deprecated and is scheduled to expire on 31 December 2020. If not fixed, the removal of graphics/mesa-libs is likely to affect this port in 2021.
(In reply to Vincent Bentley from comment #0)
Shouldn't the issue be handled by mesa-libs maintainer? Mesa is essential to a desktop system, so I don't think mesa-libs maintainer will ignore the issue.
Nothing gnome@ can do here short of disabling OPENGL option.
*** This bug has been marked as a duplicate of bug 239939 ***