[BUG] incomplete whitespace removal of unquoted expansion

[Martijn Dekker <martijn@xxxxxxxx>]

For unset foo:

dash-git
$ src/dash -c 'set -- ${foo- bar }; echo "[$1]"'
[bar ]

Release versions of dash and all other shells output:
[bar]

The change in behaviour appears to have been introduced by commit
3cd5386 ("expand: Do not reprocess data when expanding words").

- Martijn

-- 
modernish -- harness the shell
https://github.com/modernish/modernish