backport changes from ghc-7.10.3 copr as 1.6.0
    
    - ghc_gen_filelists: determine keyname with pkgnamever not just pkgname
      (fixes building newer version of installed package)
    - use _rpmconfigdir macro
    - support el6 (no fileattrs or /usr/lib/rpm/macros.d)
    - change url to github
    - add and use ghc-pkg-wrapper script
    - use ghc-pkg key field (for ghc-7.10)
    - configure libsubdir using pkgkey like ghc-cabal
    - handle no ghc-srpm-macros for fedora < 21
    - fix ghc-pkg path in ghc-deps.sh for ghc-7.10
    - version ghc-pkg in ghc_pkg_recache
    - update ghc_gen_filelists to use new keyed library filepaths
      and specify libHS*.so more loosely
    - ghc-dep.sh now just makes versioned devel reqs
    - rename ghc_lib.attr to ghc.attr and drop ghc_bin.attr
    
    - enable debuginfo package