it looks like after the 8.6.2 release there was some fixes cherry picked into the 8.6 branch for the Mach O linker that I believe were the cause of the errors i've been seeing, i'm doing a fresh build to confirm

On Tue, Nov 27, 2018 at 12:03 PM Carter Schonwald <carter.schonwald@gmail.com> wrote:
the vast majority of the errors i previously shared seem to be 

"can't find atom for stabs BNSYM at 0000AF80 in /Users/carter/dev-checkouts/ghc-tree/ghc-8.6.X-checkout-clang-build/libraries/base/dist-install/build/libHSbase-4.12.0.0.a(Internals.o)"

which corresponds with this code in the apple linker

i dont know to what to make of this