[RFA] Use unique_xmalloc_ptr for read_string

[Simon Marchi]

On 2018-05-21 16:41, Tom Tromey wrote:
> This changes read_string's "buffer" out-parameter to be a
> unique_xmalloc_ptr, then updates the users.  This allows for the
> removal of some cleanups.
> 
> I chose unique_xmalloc_ptr rather than byte_vector here due to the way
> Guile unwinding seems to work.

Hmm yeah I'm not too sure how Guile exceptions, work.  Would the 
destructor of a an object local to gdbscm_value_to_string run, if 
scm_from_stringn was to throw an exception, I guess that's the question?

In any case, your patch LGTM.

Simon