vkdt: enable rawler for rawinput

By default, vkdt checks for rustc presence during build to enable raw
input with rawler. This breaks in the nix build, since rustc is not on
PATH. This force-enables raw input via rawler through a make flag,
similar to the upstream flake.

See hanatos/vkdt#201 for upstream discussion of this issue.

pkgs/by-name/vk/vkdt/package.nix

@@ -81,6 +81,7 @@ stdenv.mkDerivation rec {
   makeFlags = [
     "DESTDIR=$(out)"
     "prefix="
+    "VKDT_USE_RAWINPUT=2"
     "VKDT_USE_MCRAW=false" # TODO: support mcraw
   ];