haskell: fix missing cabal file after prePatch for various packages (#447488)

pkgs/by-name/ec/echidna/package.nix

@@ -96,7 +96,7 @@ haskellPackages.mkDerivation rec {
     makeWrapper
   ];
 
-  preConfigure = ''
+  prePatch = ''
     hpack
   '';
 

pkgs/development/tools/haskell/vaultenv/default.nix

@@ -46,6 +46,7 @@ mkDerivation rec {
   prePatch = ''
     substituteInPlace package.yaml \
         --replace -Werror ""
+    hpack
   '';
 
   isLibrary = false;
@@ -82,7 +83,6 @@ mkDerivation rec {
     hspec-expectations
     quickcheck-instances
   ];
-  preConfigure = "hpack";
   homepage = "https://github.com/channable/vaultenv#readme";
   description = "Runs processes with secrets from HashiCorp Vault";
   license = lib.licenses.bsd3;

pkgs/tools/misc/fffuu/default.nix

@@ -16,17 +16,17 @@ mkDerivation {
     sha256 = "1qc7p44dqja6qrjbjdc2xn7n9v41j5v59sgjnxjj5k0mxp58y1ch";
   };
 
+  postUnpack = ''
+    sourceRoot="$sourceRoot/haskell_tool"
+  '';
+
   postPatch = ''
-    substituteInPlace haskell_tool/fffuu.cabal \
+    substituteInPlace fffuu.cabal \
       --replace "containers >=0.5 && <0.6" "containers >= 0.6" \
       --replace "optparse-generic >= 1.2.3 && < 1.3" "optparse-generic >= 1.2.3" \
       --replace "split >= 0.2.3 && <= 0.2.4" "split >= 0.2.3"
   '';
 
-  preCompileBuildDriver = ''
-    cd haskell_tool
-  '';
-
   isLibrary = false;
 
   isExecutable = true;