davide authored Apr 30, 2019 and Marge Bot committed May 10, 2019

In Hadrian, building programs (e.g. `ghc` or `haddock`) requires libraries located in the ghc-pkg package database i.e.

    _build/stage1/lib/x86_64-linux-ghc-8.9.0.20190430/libHSdeepseq-1.4.4.0-ghc8.9.0.20190430.so

Add the corresponding `need`s for these library files and the subsequent rules.