message: Hide readlink error in `./miri`
  `./miri` is just testing whether the platform supports `readlink -e`,
  but it didn't hide properly hide the stderr output. This fixes that.
diff: @@ -40,7 +40,7 @@ TARGET=$(rustc --version --verbose | grep "^host:" | cut -d ' ' -f 2)
  SYSROOT=$(rustc --print sysroot)
  LIBDIR=$SYSROOT/lib/rustlib/$TARGET/lib
  MIRIDIR=$(dirname "$0")
  -if readlink -e . >/dev/null; then
  +if readlink -e . &>/dev/null; then
  # This platform supports `readlink -e`.
  MIRIDIR=$(readlink -e "$MIRIDIR")
  fi
  