(smb_extended_info): Move here from path.cc.
(fs_info::update): Ditto.
(mount_info::create_root_entry): Delay conversion to slashes and use passed in
buffer to figure out fs type.
* path.cc (smb_extended_info): Move.
(fs_info::update): Ditto.
* mount.h: New file. Move mount information here.
* path.h: (fs_info::update): Move.
* shared_info.h (mount_item): Ditto.