linker error in haddock, D1558

[Alan & Kim Zimmerman]

Does anyone know why a build would be failing with

utils/haddock/dist/build/Haddock/GhcUtils.dyn_o: In function `skOK_info':
(.text+0x75c8): undefined reference to `stg_ap_0_upd_info'
utils/haddock/dist/build/Haddock/GhcUtils.dyn_o: In function `skP5_info':
(.text+0x7728): undefined reference to `stg_ap_0_upd_info'
collect2: error: ld returned 1 exit status
`gcc' failed in phase `Linker'. (Exit code: 1)
utils/haddock/ghc.mk:21: recipe for target
'utils/haddock/dist/build/tmp/haddock' failed
make[1]: *** [utils/haddock/dist/build/tmp/haddock] Error 1

This is happening on
https://phabricator.haskell.org/harbormaster/build/8393/, a build of
https://phabricator.haskell.org/D1558

Alan
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