MySQL authentication and operating system authentication have never been integrated.
It's not supported to synchronize MySQL users with Kerberos, Windows Domains, LDAP, PAM, SSO, or any other system-wide or site-wide authentication database. Nor is there any announced plans to improve MySQL in this direction, according to their various roadmap docs.
Kerberos is mentioned in this feature request:
http://bugs.mysql.com/bug.php?id=6733
My workaround is to use only a few "role"-like MySQL accounts, for example "users", "backup" or "root". The application (in my case, I mostly work on web apps) is responsible for the more fine-grained user authentication. It's much easier to integrate web apps into whatever site-wide authentication system you use. Apache, PHP, Tomcat, etc. all have support for Kerberos.
Regards,
Bill K.