Andrey and other Hadrian heros

Just to say that I am 100% stalled on using Hadrian because the in-tree binary uses the wrong library files.  I reported this a few weeks ago, but it still seems unchanged

Simon

Bash$ ~/code/HEAD/_build/stage0/bin/ghc --version

The Glorious Glasgow Haskell Compilation System, version 8.9.0.20190414

simonpj@MSRC-3645512:~/tmp$ ~/code/HEAD/_build/stage0/bin/ghc -c T16566.hs

T16566.hs:1:8: error:

    Bad interface file: /opt/ghc/8.6.4/lib/ghc-8.6.4/base-4.12.0.0/Prelude.hi

        mismatched interface file versions (wanted "809020190414", got "8064")

  |

1 | module T16566 where

  |        ^^^^^^