Subdirectory Recurse for `-i`

[tinygiant98]

The -i argument accepts a semi-colon delimited list of paths to search for include files, but doesn't appear to recurse or respond to glob patterns. Subfolders appear to require a separate entry in the list. Is it possible to allow the -i argument to resolve subdirectories via a glob, SearchOption.AllDirectories, or a getSubDirs routine that will populate a std::vector (as is already used) with subdirectory paths, possibly based on an additional switch (such as -I = include all subdirectories whereas -i includes only the listed folder) or the like)?