Add local package for Maude

The "official" package for Maude is broken on darwin. This one downloads and
installs the binary. Not as nice as building from source, but much easier...

flake.nix

@@ -69,6 +69,8 @@
                     ./patches/system-appearance.patch
                   ];
                 });
+
+               maude-mac = final.callPackage ./pkgs/maude-mac {};
               })
             ];
           };

modules/home.nix

@@ -37,6 +37,7 @@
     htop
     inkscape
     leiningen
+    maude-mac
     nixpkgs-fmt
     jdk
     pandoc

pkgs/maude-mac/default.nix

@@ -0,0 +1,39 @@
+{ lib, stdenv, fetchurl, unzip, ... }:
+
+stdenv.mkDerivation rec {
+  pname = "maude";
+  version = "3.2.1";
+
+  src = fetchurl {
+    url = "https://github.com/SRI-CSL/Maude/releases/download/${version}/Maude-${version}-macos.zip";
+    sha256 = "sha256-m+bgdYzzoQq6knrUkRtr3rXqHLNgr3kquKzuSUIDa2I=";
+  };
+
+  nativeBuildInputs = [ unzip ];
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp *.maude $out/bin/
+    cp maude.Darwin64 $out/bin/maude
+  '';
+
+  meta = with lib; {
+    homepage = "http://maude.cs.illinois.edu/";
+    description = "High-level specification language";
+    license = lib.licenses.gpl2Plus;
+
+    longDescription = ''
+      Maude is a high-performance reflective language and system
+      supporting both equational and rewriting logic specification and
+      programming for a wide range of applications. Maude has been
+      influenced in important ways by the OBJ3 language, which can be
+      regarded as an equational logic sublanguage. Besides supporting
+      equational specification and programming, Maude also supports
+      rewriting logic computation.
+    '';
+
+    sourceProvenance = with sourceTypes; [ binaryNativeCode ];
+    platforms = platforms.darwin;
+    maintainers = with maintainers; [ larstvei ];
+  };
+}