ghc-deps.sh: split off buildroot from the ghclibdir arg for more precise paths
    
    This allows using the ghclibdir for checking for prof libs,
    avoiding collisions with other ghcX.Y-*-prof files:
    
    Processing files: ghc-doctemplates-prof-0.9-7.fc37.x86_64
    /usr/lib/rpm/ghc-deps.sh: line 60: [: too many arguments
    /usr/lib/rpm/ghc-deps.sh: line 60: [: too many arguments
    /usr/lib/rpm/ghc-deps.sh: line 60: [: too many arguments