Maybe actually fix builds

nix/wasm.nix

@@ -0,0 +1,35 @@
+{ buildGoModule, go, lib, ... }:
+
+let
+  pkg = builtins.fromJSON (builtins.readFile ../package.json);
+  pname = "hp_ssh-wasm";
+  version = pkg.version;
+  wasmExecJs =
+    if builtins.pathExists "${go}/share/go/lib/wasm/wasm_exec.js" then
+      "${go}/share/go/lib/wasm/wasm_exec.js"
+    else if builtins.pathExists "${go}/lib/wasm/wasm_exec.js" then
+      "${go}/lib/wasm/wasm_exec.js"
+    else
+      "${go}/share/go/misc/wasm/wasm_exec.js";
+in
+buildGoModule rec {
+  inherit pname version;
+  src = ../.;
+  subPackages = [ "cmd/hp_ssh" ];
+  vendorHash = "sha256-3hZzDORAH+D4FW6SkOv3Enddd+q36ZALryvCPD9E5Ac=";
+  env.CGO_ENABLED = 0;
+
+  nativeBuildInputs = [ go ];
+
+  buildPhase = ''
+    export GOOS=js
+    export GOARCH=wasm
+    go build -o hp_ssh.wasm ./cmd/hp_ssh
+  '';
+
+  installPhase = ''
+    mkdir -p $out
+    cp hp_ssh.wasm $out/
+    cp ${wasmExecJs} $out/wasm_exec.js
+  '';
+}