[PATCH] libio: Update number of written bytes in dprintf implementation

[Florian Weimer]

* Andreas Schwab:

> On Jan 31 2023, Florian Weimer via Libc-alpha wrote:
>
>> The __printf_buffer_flush_dprintf function needs to record that
>> the buffer has been written before reusing it.  Without this
>> accounting, dprintf always returns zero.
>>
>> Fixes commit 8ece45e4f586abd212d1c02d74d38ef681a45600
>> ("libio: Convert __vdprintf_internal to buffers.
>                                                  ")

Thanks, fixed locally:

    libio: Update number of written bytes in dprintf implementation
    
    The __printf_buffer_flush_dprintf function needs to record that
    the buffer has been written before reusing it.  Without this
    accounting, dprintf always returns zero.
    
    Fixes commit 8ece45e4f586abd212d1c02d74d38ef681a45600
    ("libio: Convert __vdprintf_internal to buffers").

Florian