cardinal: fix cross-compilation (#357454)

pkgs/by-name/ca/cardinal/package.nix

@@ -1,28 +1,29 @@
-{ stdenv
-, fetchurl
-, cmake
-, dbus
-, fftwFloat
-, file
-, freetype
-, jansson
-, lib
-, libGL
-, libX11
-, libXcursor
-, libXext
-, libXrandr
-, libarchive
-, libjack2
-, liblo
-, libsamplerate
-, libsndfile
-, makeWrapper
-, pkg-config
-, python3
-, speexdsp
-, libglvnd
-, headless ? false
+{
+  stdenv,
+  fetchurl,
+  cmake,
+  dbus,
+  fftwFloat,
+  file,
+  freetype,
+  jansson,
+  lib,
+  libGL,
+  libX11,
+  libXcursor,
+  libXext,
+  libXrandr,
+  libarchive,
+  libjack2,
+  liblo,
+  libsamplerate,
+  libsndfile,
+  makeWrapper,
+  pkg-config,
+  python3,
+  speexdsp,
+  libglvnd,
+  headless ? false,
 }:
 
 stdenv.mkDerivation rec {
@@ -69,7 +70,13 @@ stdenv.mkDerivation rec {
   ];
 
   hardeningDisable = [ "format" ];
-  makeFlags = lib.optional headless "HEADLESS=true" ++ [ "SYSDEPS=true" "PREFIX=$(out)" ];
+  makeFlags =
+    [
+      "SYSDEPS=true"
+      "PREFIX=$(out)"
+    ]
+    ++ lib.optional (stdenv.hostPlatform != stdenv.buildPlatform) "CROSS_COMPILING=true"
+    ++ lib.optional headless "HEADLESS=true";
 
   postInstall = ''
     wrapProgram $out/bin/Cardinal \
@@ -86,7 +93,10 @@ stdenv.mkDerivation rec {
     description = "Plugin wrapper around VCV Rack";
     homepage = "https://github.com/DISTRHO/cardinal";
     license = lib.licenses.gpl3;
-    maintainers = with lib.maintainers; [ magnetophon PowerUser64 ];
+    maintainers = with lib.maintainers; [
+      magnetophon
+      PowerUser64
+    ];
     mainProgram = "Cardinal";
     platforms = lib.platforms.all;
     # never built on aarch64-darwin, x86_64-darwin since first introduction in nixpkgs