Account for the fact that, when creating a lua package without the
"withPackages" helper, we dont get an extra "lua" attribute in the
package.
Therefore we need to distinguish between the "withPackages" case and the
direct ( or "empty" ) lua package.
For example with this nixos config:
```nix
{
services.httpd = {
enable = true;
package = pkgs.apacheHttpd.override {
luaSupport = true;
lua5 = pkgs.lua5_3.withPackages (ps: with ps; [ luafilesystem ] );
};
};
}
```
Here we say that we want to have apache to use a lua, packaged with the
`luafilesystem` module so that we can `require` that in scripts to
render http responses. There, the set that gets assigned to `lua5 ` does
not have a `luaversion` attribute, rather it has a `lua` attribute
wherein lies a `luaversion` attribute. If we dont package additional
modules, then we dont have that `lua` attribute in between and rather
directly have to use `luaversion` directly.
7c121e60c5