fixed an error in fseek when reading backtrace in the error log.

[shukean]

my_fseek return MY_FILEPOS_ERROR (-1) if failed.

It also exists in version 8.4.

[mysql-oca-bot]

Hi, thank you for submitting this pull request. In order to consider your code we need you to sign the Oracle Contribution Agreement (OCA). Please review the details and follow the instructions at https://oca.opensource.oracle.com/
Please make sure to include your MySQL bug system user (email) in the returned form.
Thanks

[shukean]

Hi, thank you for submitting this pull request. In order to consider your code we need you to sign the Oracle Contribution Agreement (OCA). Please review the details and follow the instructions at https://oca.opensource.oracle.com/ Please make sure to include your MySQL bug system user (email) in the returned form. Thanks

568089266@qq.com

[mysql-oca-bot]

Hi, there was no response to our request to sign an OCA or confirm the code is submitted under the terms of the OCA. As such this request will be closed.
Thanks