When building Hyprland in nix using the following home-manager recipe:
```nix
wayland.windowManager.hyprland = {
enable = true;
xwayland = false;
};
```
The default nix configuration still makes reference to a compile argument `NO_XWAYLAND`, but the `meson_options.txt` only makes reference to `xwayland`. This causes the build to fail with:
```
meson.build:1:0: ERROR: Unknown options: "NO_XWAYLAND"
```
This change fixes that issue. This still doesn't allow you to build Hyprland without having XWayland installed (#178), but it should at least allow for valid nix configurations for when that issue gets resolved.