One example that came up recently is http://beefy10.nyi.freebsd.org/data/112i386-default/486388/logs/pcl-pointclouds-1.9.1.log, but there are other examples that have BROKEN_i386 for this reason.
Failure looks something like this:
> lib/libpcl_surface.so.1.9.1: undefined reference to `__atomic_load'
> clang-7: error: linker command failed with exit code 1 (use -v to see invocation)
*** This bug has been marked as a duplicate of bug 230888 ***