Under autoconf 2.69c (beta) `./configure` fails as:

```
./configure
...
checking for msgfmt... msgfmt
./configure: line 7441: syntax error near unexpected token `newline'
./configure: line 7441: `    '''
```

This happens due to underquoting of a snippet
argument for `AS_VAR_SET_IF` call.
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>