drop ghc_compiler and use generic devel description

ghc-case-insensitive.spec

@@ -30,13 +30,14 @@ type will be insensitive to cases.
 
 %package devel
 Summary:        Haskell %{pkg_name} library development files
-Requires:       %{ghc_compiler}
-Requires(post): %{ghc_compiler}
-Requires(postun): %{ghc_compiler}
+Requires:       ghc-compiler = %{ghc_version}
+Requires(post): ghc-compiler = %{ghc_version}
+Requires(postun): ghc-compiler = %{ghc_version}
 Requires:       %{name} = %{version}-%{release}
 
 %description devel
-This package provides the Haskell case-insensitive library development files.
+This package provides the Haskell %{pkg_name} library development files.
+
 
 %prep
 %setup -q -n %{pkg_name}-%{version}