To follow up.

Using GDC, I used GCC 11.2.0, as bootstrap is the only way to build LDC on powerpc64.  The resulting LDC can not be used to build itself, for some reason. However it can be used to build dub and other dlang libraries and tools.  I highly recommend only building dub (devel/dub) from the freebsd ports.  Then use dub to build everything else, including itself, outside ports.

DRuntime PR #2628, 'Add unittests for load/store Unaligned in core.simd', prevents the building of unit-test "druntime-test-runner".  Reversing this PR allows all tests to be run, with approximately 50 failed tests.  No research has been done on these failures.

These results are for big endian powerpc64.  I've had mixed results on powerpc64le, but I don't think they're exclusively related to LDC.  I think I corrupted my powerpc64le install when I did a source upgrade from the freebsd 13 beta version to the freebsd 13 release version.  A lot of previously working apps are no longer working.  I'm going to do a clean re-install of freebsd/powerpc64le and rebuild everything before trying again.