boop-gtk: tweak installPhase

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:msfjarvis/nixpkgs/3161bfe9839364daaef5af59f3a0d756336a9ff8?narHash=sha256-AUGJwYW9/7YeJLMb8vTjZzHEpR0omxUTHZhUgQP1ngg%3D' (2024-04-30)
  → 'github:msfjarvis/nixpkgs/ccacdbec0588554547fa54cb83edccf45936a378?narHash=sha256-FB%2Bh671mf97Unz/vpbCO3ZpizGzIxnIIdy4LpSTzf6k%3D' (2024-04-30)

flake.lock

@@ -652,11 +652,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1714453200,
-        "narHash": "sha256-AUGJwYW9/7YeJLMb8vTjZzHEpR0omxUTHZhUgQP1ngg=",
+        "lastModified": 1714504286,
+        "narHash": "sha256-FB+h671mf97Unz/vpbCO3ZpizGzIxnIIdy4LpSTzf6k=",
         "owner": "msfjarvis",
         "repo": "nixpkgs",
-        "rev": "3161bfe9839364daaef5af59f3a0d756336a9ff8",
+        "rev": "ccacdbec0588554547fa54cb83edccf45936a378",
         "type": "github"
       },
       "original": {

packages/boop-gtk/default.nix

@@ -69,11 +69,9 @@ rustPlatform.buildRustPackage rec {
     })
   ];
 
-  installPhase = let
-    arch = rust.toRustTarget stdenv.hostPlatform;
-  in ''
+  installPhase = ''
     runHook preInstall
-    install -Dm755 target/${arch}/release/boop-gtk $out/bin/boop-gtk
+    install -Dm755 target/${stdenv.hostPlatform.rust.cargoShortTarget}/release/boop-gtk $out/bin/boop-gtk
     install -Dm644 data/fyi.zoey.Boop-GTK.png $out/share/icons/hicolor/64x64/${pname}.png
     runHook postInstall
   '';