"CLASS->safe_quote ITEM"

Quotes an item to become safe against spaces in shell interpolation. An item is enclosed in double quotes if:

- the item contains spaces in the middle
- the item does not start with a quote

This happens to avoid shell interpolation problems when whitespace is present in directory names.

This method uses "commands_quote" to determine the correct quote. If "commands_quote" is a space, no quoting will take place.

if it starts and ends with the same quote character: leave it as it is

if it contains no whitespace: leave it as it is

if it contains whitespace, then

if it contains quotes: better leave it as it is

else: quote it with the correct quote type for the box we're on