ghc: revert "propagate 'gmp' and 'ncurses' to ensure users can link the 'haskeline' library, etc."

I thought that [1] could be fixed by ensuring that ncurses is available in the
environment (because ghc exports it as a propagateBuildInput), and indeed that
change fixed *some* build failures we've had before. However, the same error
still occurs with other packages, like hledger [2] and Agda [3]. Frankly, I
have no idea why those packages fail and others don't. But clearly the fix was
inadequate, so I'm reverting commit a8076c76.

[1] https://github.com/NixOS/nixpkgs/issues/5616
[2] http://hydra.cryp.to/build/372451/nixlog/1/raw
[2] http://hydra.cryp.to/build/373161/nixlog/1/raw

pkgs/development/haskell-modules/configuration-ghc-7.6.x.nix

@@ -16,7 +16,7 @@ self: super: {
   directory = null;
   filepath = null;
   ghc-prim = null;
-  haskeline = null;
+  haskeline = self.haskeline_0_7_1_3;   # GHC's version is broken: https://github.com/NixOS/nixpkgs/issues/5616.
   haskell2010 = null;
   haskell98 = null;
   hoopl = null;
@@ -28,7 +28,7 @@ self: super: {
   process = null;
   rts = null;
   template-haskell = null;
-  terminfo = null;
+  terminfo = self.terminfo_0_4_0_0;     # GHC's version is broken: https://github.com/NixOS/nixpkgs/issues/5616.
   time = null;
   unix = null;
 

pkgs/development/haskell-modules/configuration-ghc-7.8.x.nix

@@ -16,7 +16,7 @@ self: super: {
   directory = null;
   filepath = null;
   ghc-prim = null;
-  haskeline = null;
+  haskeline = self.haskeline_0_7_1_3;   # GHC's version is broken: https://github.com/NixOS/nixpkgs/issues/5616.
   haskell2010 = null;
   haskell98 = null;
   hoopl = null;
@@ -28,7 +28,7 @@ self: super: {
   process = null;
   rts = null;
   template-haskell = null;
-  terminfo = null;
+  terminfo = self.terminfo_0_4_0_0;     # GHC's version is broken: https://github.com/NixOS/nixpkgs/issues/5616.
   time = null;
   transformers = null;
   unix = null;

pkgs/development/haskell-modules/generic-builder.nix

@@ -129,7 +129,7 @@ stdenv.mkDerivation ({
     mkdir -p $packageConfDir
 
     local inputClosure=""
-    for i in $propagatedNativeBuildInputs $nativeBuildInputs ${ghc}; do
+    for i in $propagatedNativeBuildInputs $nativeBuildInputs; do
       findInputs $i inputClosure propagated-native-build-inputs
     done
     for p in $inputClosure; do