Allow customizing the nixpkgs version from the default.nix using addi…

…tionalNixpkgsOptions. Additionally use makeWrapper to wrap runtime dependencies on the output binary

This is needed for better supporting cross-compiling IHP apps.

Requires the project's Config/nix/nixpkgs-config.nix to be migrated to this:
```nix
{ ihp, additionalNixpkgsOptions }:
import "${toString ihp}/NixSupport/make-nixpkgs-from-options.nix" {
    ihp = ihp;
    additionalNixpkgsOptions = additionalNixpkgsOptions;
    haskellPackagesDir = ./haskell-packages/.;
}
```

NixSupport/default.nix

@@ -1,14 +1,21 @@
-{ compiler ? "ghc8104", ihp, haskellDeps ? (p: []), otherDeps ? (p: []), projectPath ? ./., withHoogle ? false }:
+{ compiler ? "ghc8104"
+, ihp
+, haskellDeps ? (p: [])
+, otherDeps ? (p: [])
+, projectPath ? ./.
+, withHoogle ? false
+, additionalNixpkgsOptions ? {}
+}:
 
 let
-    pkgs = import "${toString projectPath}/Config/nix/nixpkgs-config.nix" { ihp = ihp; };
+    pkgs = import "${toString projectPath}/Config/nix/nixpkgs-config.nix" { ihp = ihp; additionalNixpkgsOptions = additionalNixpkgsOptions; };
     ghc = pkgs.haskell.packages.${compiler};
     allHaskellPackages =
       (if withHoogle
       then ghc.ghcWithHoogle
       else ghc.ghcWithPackages)
         (p: builtins.concatLists [ [p.haskell-language-server] (haskellDeps p) ] );
-    allNativePackages = builtins.concatLists [ (otherDeps pkgs) [pkgs.postgresql] (if pkgs.stdenv.isDarwin then [] else []) ];
+    allNativePackages = builtins.concatLists [ (otherDeps pkgs) [pkgs.postgresql pkgs.makeWrapper] (if pkgs.stdenv.isDarwin then [] else []) ];
 in
     pkgs.stdenv.mkDerivation {
         name = "app";
@@ -23,8 +30,15 @@ in
           make -B build/bin/RunUnoptimizedProdServer
         '';
         installPhase = ''
-          mkdir -p $out
-          cp -r build/bin $out/bin
+          mkdir -p "$out"
+          mkdir -p $out/bin
+
+          mv build/bin/RunUnoptimizedProdServer $out/bin/RunUnoptimizedProdServer
+          makeWrapper $out/bin/RunUnoptimizedProdServer $out/bin/RunProdServer --prefix PATH : ${pkgs.lib.makeBinPath (otherDeps pkgs)}
+
+          mkdir -p "$out/lib/build"
+          cp -R "${ihp}/lib" "$out/lib/build/ihp-lib"
+          mv static "$out/lib/static"
         '';
         dontFixup = true;
         src = (import <nixpkgs> {}).nix-gitignore.gitignoreSource [] projectPath;

NixSupport/make-nixpkgs-from-options.nix

@@ -10,6 +10,7 @@
 , nixPkgsSha256 ? "0kfrw1mvpx2nkr493iq6bw0d6cxdwrmp6xqsir20bhmqwr36sds7"
 , compiler ? "ghc8104"
 , manualOverrides ? haskellPackagesNew: haskellPackagesOld: { } # More exotic overrides go here
+, additionalNixpkgsOptions ? {}
 }:
 let
   generatedOverrides = haskellPackagesNew: haskellPackagesOld:
@@ -75,7 +76,7 @@ let
     repo = "nixpkgs";
     rev = nixPkgsRev;
     sha256 = nixPkgsSha256;
-  })) { inherit config; };
+  })) ({ inherit config; } // additionalNixpkgsOptions);
 
 in
     pkgs