cabal2spec format for ghc-rpm-macros requires

ghc-HTTP.spec

@@ -19,8 +19,7 @@ Source0:        http://hackage.haskell.org/packages/archive/%{pkg_name}/%{versio
 BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 # fedora ghc archs:
 ExclusiveArch:  %{ix86} x86_64 ppc alpha
-BuildRequires:  ghc
+BuildRequires:  ghc, ghc-rpm-macros
-BuildRequires:  ghc-rpm-macros
 %if %{with doc}
 BuildRequires:  ghc-doc
 %endif