add libunwind

default.nix

@@ -54,6 +54,7 @@ let
     pkg-config = pkgs.pkg-config;
     buildNoDefaultFeatures = !defaultFeatures;
     buildFeatures = lib.strings.splitString "," features;
+    libunwind = pkgs.libunwind;
   };
 
   # HACK: https://github.com/NixOS/nixpkgs/issues/177129

package.nix

@@ -1,4 +1,5 @@
 { lib
+, libunwind
 , pkg-config
 , rustPlatform
 , windows
@@ -31,10 +32,11 @@ rustPlatform.buildRustPackage rec {
 
   NIX_LDFLAGS = lib.optionals (stdenv.hostPlatform.isWindows && stdenv.hostPlatform.isi686) [
     "-L${windows.mcfgthreads}/lib"
+    "-L${libunwind}/lib"
     # "-L${windows.mingwrt}/lib"
     #"-L${windows.w32api}/lib"
     "-lmcfgthread"
-    #"-lunwind"
+    "-lunwind"
   ];
 
   # unit tests only