provide ghc-devel, use ghc_without_shared, strip all dynlinked files
    
    - provide ghc-devel for compatibility with cabal2spec-0.22.5
    - use ghc_without_shared
    - drop buildroot and buildroot cleaning
    - smp build with max 4 cpus
    - strip all dynlinked files not just shared objects (ghc-rpm-macros-0.5.9)