Runtime equivalent of collectFiles. This version uses std.file to read files from the appropriate directory. Note that for collectFiles, the directory to use is passed on the command line, whereas in this case, we must receive the directory containing the files from the caller.
string baseDir = ""
|The root file that will be used to find all referenced files.
|Optional base directory from which all files will be searched.
An array of InputFile structs containing the list of files that are referenced from the root file, and their contents.