* sigproc.cc (_pinfo::set_ctty): Move function

* sigproc.cc (_pinfo::set_ctty): Move function
* pinfo.cc (_pinfo::set_ctty): to here.
* fhandler_mem.cc (fhandler_dev_mem::fstat): Don't fill out structure if this
is an on-disk device rather than an "auto" device.
* fhandler_raw.cc (fhandler_dev_raw::fstat): Ditto.
* path.cc (normalize_posix_path): Don't treat a standalone '//' as introducing
a UNC path.
(normalize_win32_path): Ditto.