cachix: use separate bin output to prove it's useful

Spares compilation time by not compiling the package twice.

(cherry picked from commit b06201b)
Signed-off-by: Domen Kožar <domen@dev.si>

pkgs/development/haskell-modules/configuration-nix.nix

@@ -94,6 +94,8 @@ self: super: builtins.intersectAttrs super {
   # Won't find it's header files without help.
   sfml-audio = appendConfigureFlag super.sfml-audio "--extra-include-dirs=${pkgs.openal}/include/AL";
 
+  cachix = enableSeparateBinOutput super.cachix;
+
   hzk = overrideCabal super.hzk (drv: {
     preConfigure = "sed -i -e /include-dirs/d hzk.cabal";
     configureFlags =  "--extra-include-dirs=${pkgs.zookeeper_mt}/include/zookeeper";

pkgs/development/tools/cachix/default.nix

@@ -1,8 +1,3 @@
 { haskellPackages, haskell }:
 
-(haskellPackages.override {
-  overrides = self: super: {
-    cachix = haskell.lib.justStaticExecutables (super.callPackage ./cachix.nix {});
-    cachix-api = super.callPackage ./cachix-api.nix {};
-  };
-}).cachix
+(haskell.lib.doDistribute haskellPackages.cachix).bin

pkgs/top-level/all-packages.nix

@@ -9498,11 +9498,7 @@ in
 
   c-blosc = callPackage ../development/libraries/c-blosc { };
 
-  cachix = (callPackage ../development/tools/cachix { }).overrideAttrs (drv: {
-    meta = drv.meta // {
-      hydraPlatforms = stdenv.lib.platforms.unix;
-    };
-  });
+  cachix = callPackage ../development/tools/cachix { };
 
   capnproto = callPackage ../development/libraries/capnproto { };