ugarit: fix build by using CHICKEN 4.x
ugarit: fix build by using CHICKEN 4.x

Ugarit only works with CHICKEN 4, not CHICKEN 5 (which is the default
version in nixpkgs since 69ef0702), so use the compiler and egg tools
from `chickenPackages_4` for ugarit and ugarit-manifest-maker.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs