No errors previous to compiling mysql headers.
It then completed by cleaning out the /tmp/install_ispconfig but setup script still continued and tried to unpack spamassassin, apr.tar.gz and many other packages after mysql.
Setup exited with a ispconfig installation complete message and proceeded to launch ispconfig. But it failed to start normal apache since cronolog wasn't compiled and had been removed out of /root/ispconfig . A lot of other directories under that directory were also empty.
The backup files created by setup were also removed from /tmp since setup script had succeded (at least it thought so), luckily I always proceed to store another backup before upgrades so I could restore my SSL conf.
Then I installed the mysql library package through apt-get, ran the setup again. Finished without errors, only thing I had to do was restore my SSL conf since that's the only thing I run custom.
But Im guessing I would've had a lot of issues if the setup hadn't upgraded mysql tables properly if there had been changes from previous versions.
Is there a way I can check to see if mysql table layout is correct?