lib/scripts/fileident

eliminated slightly odd Library/Library session setup (cf. d7711be8c3a9) which is obsolete due to usedir -f HOL_Library_ROOT.ML;

#!/usr/bin/env bash
#
# fileident --- produce file identification based

FILE="$1"

if [ -n "$ISABELLE_FILE_IDENT" -a -f "$FILE" -a -r "$FILE" ]
then
  ID=$(cat "$FILE" | $ISABELLE_FILE_IDENT | cut -d " " -f 1) && echo -n "$ID"
fi