* 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.

winsup/cygwin/pinfo.cc

@@ -373,6 +373,14 @@ _pinfo::set_ctty (tty_min *tc, int flags, fhandler_tty_slave *arch)
     }
 }
 
+/* Test to determine if a process really exists and is processing signals.
+ */
+bool __stdcall
+_pinfo::exists ()
+{
+  return this && !(process_state & PID_EXITED);
+}
+
 bool
 _pinfo::alive ()
 {