bug#37366: ghci can't find System.IO

[P via Bug reports for GNU Guix]

with the latest ghc (qhws2nyqmjansrnqf78mz87l74v01mfx-ghc-8.6.5) i cannot start 
ghci, due to the following error[1]

I do not have any other Haskell package in my profile


[1]:
```
GHCi, version 8.6.5: http://www.haskell.org/ghc/  :? for help

<interactive>:1:6: error:
    Not in scope: ‘System.IO.hSetBuffering’
    No module named ‘System.IO’ is imported.

<interactive>:1:30: error:
    Not in scope: ‘System.IO.stdin’
    No module named ‘System.IO’ is imported.

<interactive>:1:46: error:
    Not in scope: data constructor ‘System.IO.NoBuffering’
    No module named ‘System.IO’ is imported.

<interactive>:1:70: error:
    Not in scope: ‘System.IO.hSetBuffering’
    No module named ‘System.IO’ is imported.

<interactive>:1:94: error:
    Not in scope: ‘System.IO.stdout’
    No module named ‘System.IO’ is imported.

<interactive>:1:111: error:
    Not in scope: data constructor ‘System.IO.NoBuffering’
    No module named ‘System.IO’ is imported.

<interactive>:1:135: error:
    Not in scope: ‘System.IO.hSetBuffering’
    No module named ‘System.IO’ is imported.

<interactive>:1:159: error:
    Not in scope: ‘System.IO.stderr’
    No module named ‘System.IO’ is imported.

<interactive>:1:176: error:
    Not in scope: data constructor ‘System.IO.NoBuffering’
    No module named ‘System.IO’ is imported.
```