The line_buffer library silently flags input errors until
buffer_deinit time; unfortunately, by that point usually errno is
invalid. Expose the error flag so callers can check for and
report errors early for easy debugging.
some_error_prone_operation(...);
if (buffer_ferror(buf))
return error("input error: %s", strerror(errno));
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: David Barr <david.barr@cordelta.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>