Hadrian: programs need registered ghc-pkg libraries

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

This MR add's the corresponding needs for these library files and the subsequent rules.