flake.nix: remove $HOME at end of every build

It seems that crane accidentally creates these, and makes it so that the
nix builders in CI complains about leftovers.

See also: https://github.com/ipetkov/crane/issues/815

flake.nix

@@ -81,6 +81,11 @@
           inherit src;
           strictDeps = true;
         };
+
+        # https://github.com/ipetkov/crane/issues/815
+        postFixup = ''
+          [ -d "$HOME" ] && rm -rf "$HOME"
+        '';
       };
 
       tamerye-static-lib = craneLib.buildPackage {
@@ -109,6 +114,10 @@
         };
 
         cargoExtraArgs = lib.escapeShellArgs [ "--features" "static" ];
+
+        postFixup = ''
+          [ -d "$HOME" ] && rm -rf "$HOME"
+        '';
       };
 
       tamerye-tests = craneLib.cargoNextest {
@@ -135,6 +144,10 @@
         partitions = 1;
         partitionType = "count";
         cargoNextestPartitionsExtraArgs = "--no-tests=pass";
+
+        postFixup = ''
+          [ -d "$HOME" ] && rm -rf "$HOME"
+        '';
       };
     });
   };