mslicer: forcibly link against wayland

this fixes the error that it can't find wayland, but now it complains about unsupported (graphics) features

old error:
```
thread 'main' panicked at mslicer/src/main.rs:80:6:
called `Result::unwrap()` on an `Err` value: WinitEventLoop(Os(OsError { line: 80, file: "/build/mslicer-0.2.0-vendor/winit-0.29.15/src/platform_impl/linux/wayland/event_loop/mod.rs", error: WaylandError(Connection(NoWaylandLib)) }))
```

new error:
```
thread 'main' panicked at mslicer/src/main.rs:80:6:
called `Result::unwrap()` on an `Err` value: Wgpu(RequestDeviceError(RequestDeviceError { inner: Core(UnsupportedFeature(Features(POLYGON_MODE_LINE))) }))
```

pkgs/by-name/mslicer/package.nix

@@ -1,7 +1,16 @@
+# `result/bin/mslicer` fails with:
+# called `Result::unwrap()` on an `Err` value: Wgpu(RequestDeviceError(RequestDeviceError { inner: Core(UnsupportedFeature(Features(POLYGON_MODE_LINE))) }))
 {
-  lib,
-  rustPlatform,
   fetchFromGitHub,
+  lib,
+  libglvnd,
+  libxkbcommon,
+  pkg-config,
+  rustPlatform,
+  wayland,
+  wayland-scanner,
+  wayland-protocols,
+  wrapGAppsHook3,
 }:
 
 rustPlatform.buildRustPackage rec {
@@ -18,6 +27,43 @@ rustPlatform.buildRustPackage rec {
   cargoHash = "sha256-mRbEwxR6bMkybxe7H1dX4Qa1elGiw/lSSz9sSTtp1zw=";
   useFetchCargoVendor = true;
 
+  nativeBuildInputs = [
+    # cmake
+    pkg-config
+    wayland-scanner
+    # wrapGAppsHook3  #< doesn't fix `POLYGON_MODE_LINE`
+  ];
+
+  buildInputs = [
+    libglvnd
+    libxkbcommon
+    # openssl
+    wayland
+    wayland-protocols
+  ];
+
+  # from pkgs/by-name/al/alvr/package.nix, to get it to actually link against wayland
+  # RUSTFLAGS = map (a: "-C link-arg=${a}") [
+  #   "-Wl,--push-state,--no-as-needed"
+  #   # "-lEGL"
+  #   "-lwayland-client"
+  #   # "-lxkbcommon"
+  #   "-Wl,--pop-state"
+  # ];
+
+  # Force linking to libEGL, which is always dlopen()ed, and to
+  # libwayland-client & libxkbcommon, which is dlopen()ed based on the
+  # winit backend.
+  # from <repo:nixos/nixpkgs:pkgs/by-name/uk/ukmm/package.nix>
+  NIX_LDFLAGS = [
+    "--push-state"
+    "--no-as-needed"
+    "-lEGL"
+    "-lwayland-client"
+    "-lxkbcommon"
+    "--pop-state"
+  ];
+
   meta = with lib; {
     description = "An experimental open source slicer for masked stereolithography (resin) printers.";
     homepage = "https://connorcode.com/projects/mslicer";