code: private void setPackages(DocEnv env, List<String> packages) {
          ListBuffer<PackageDocImpl> packlist = new ListBuffer<PackageDocImpl>();
          for (String name : packages) {
              PackageDocImpl pkg = env.lookupPackage(name);
              if (pkg != null) {
                  pkg.isIncluded = true;
                  packlist.append(pkg);
              } else {
                  env.warning(null, "main.no_source_files_for_package", name);
              }
          }
          cmdLinePackages = packlist.toList();
      }
docs: Initialize packages information.
  
  @param env the compilation environment
  @param packages a list of package names (String)