lib/scripts/polyml-version

more generic error message, which also covers more fundamental failure;

#!/usr/bin/env bash
#
# polyml-version --- determine Poly/ML runtime system version

echo -n polyml

if [ -x "$ML_HOME/poly" ]; then
  if [ -x "$ML_HOME/polyimport" ]; then
    env LD_LIBRARY_PATH="$ML_HOME:$ML_HOME/../lib:$LD_LIBRARY_PATH" \
      DYLD_LIBRARY_PATH="$ML_HOME:$ML_HOME/../lib:$DYLD_LIBRARY_PATH" \
      "$ML_HOME/poly" -v | \
      sed -n 's,^Poly/ML.*RTS version: [^ ]*\(-[^ ]*\).*$,\1,p'
  else
    "$ML_HOME/poly" -noDisplay -r /dev/null | head -n 1 | \
      sed -n 's,^Poly/ML RTS version [^ ]*\(-[^ ]*\).*$,\1,p'
  fi
fi