Fix T15729 in master
Fix T15729 in master

Summary:
It failed when running ./validate on master
T15729 is added by me in D5219 recently,
it failed when GHCi is dynamicly linked:

```
Stderr ( T15729 ):
/bin/ld.gold: error: bss.o: requires unsupported dynamic reloc 11;
recompile with -fPIC
collect2: error: ld returned 1 exit status
`gcc' failed in phase `Linker'. (Exit code: 1)
```

Test Plan: Both tests pass now.

Reviewers: simonmar, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, carter

Differential Revision: https://phabricator.haskell.org/D5235

sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc