Currently this script doesn't set the indentation style for the standard
library headers under libstdc++/ because they lack a file extension.
But they do have a modeline, so the file type is still set appropriately
by Vim. So by inspecting &filetype, we can also detect these standard
library headers as C-like files.
contrib/ChangeLog:
* vimrc (SetStyle): Also inspect &filetype to determine whether
a file is C-like.
