How to use batch files to create an executable for a model which has model references?

• Through a suitable hook - like postCodeGen - you can programmatically construct a master script to call the individual makefiles / bat scripts. 
• You can access the list of referenced models by querying 'buildInfo.ModelRefs'. BuildInfo is one of the auto-generated artifacts in the form of a MAT file, which you can load and access its data.
• Here's some pseudocode that will compose paths of Model Reference libraries (and rtwsharedlib)

% Extract referenced model info
mdls = args.buildInfo.ModelRefs;

% Find the path of the directory code generation was started from
startDir = args.buildInfo.Settings.LocalAnchorDir;

% Initialize empty cell for path info
paths = cell(size(mdls));

% Additional Code for the Relative Directory
% Determine your current working directory
currentDir = pwd;

% Remove the starting directory from the current directory, this will leave
% only the path from the starting directory to the current folder.
pathFromAnchor = currentDir(2+length(startDir):end);

% Extract all the folders between the starting directory and the current
% directory
folders = strsplit(pathFromAnchor,'\');

% Create the relative path to the start directory based on the number of
% folders between the start and current directories.
relativePath = repmat('../',1,length(folders));

% If there are model references loop over them and construct the path for
% each reference

if ~isempty(mdls)
  for i = 1:length(mdls)
      libname = mdls(i).Name;
      fullpath = replace(mdls(i).Path,'$(START_DIR)\', relativePath);
      paths{i} = [fullpath,'\',libname];
  end
end