Draft: gir: Generate GLib-2.0.gir using a --filelist

This was an attempt to bypass Windows' cmd.exe command-line length limit (8191 characters according to Microsoft documentation) by ensuring we only need enough space in argv for the list of files (passed to the small script that generates the file-list) or all the other options such as --include, but not both at the same time; but it seems that limit is not the root cause of #456.