- update macros.ghc to latest proposed revised packaging guidelines:
    - use runghc
    - drop trivial cabal_build and cabal_haddock macros
    - ghc_register_pkg and ghc_unregister_pkg replace ghc_preinst_script,
        ghc_postinst_script, ghc_preun_script, and ghc_postun_script
    - lib templates' prof subpackage requires main library again
    - make cabal2spec work on .cabal files too, and read and check name and
        version directly from .cabal file
    - ghc-prof does not need to own libraries/ dirs owned by main package