buffer_putnlflush - write '\n' to buffer and flush

       buffer_putnlflush writes a single ASCII new-line character ('\n') to b and calls buffer_flush(b).

       buffer_putnlflush - write '\n' to buffer and flush

       0 if everything is fine, -1 on error (setting errno).

buffer_puts(3), buffer_put(3), buffer_flush(3), buffer(3)

                                                                                            buffer_putnlflush(3)

#include<libowfat/buffer.h>

       int buffer_putnlflush(buffer* b);