But it does not work on my system.
Reading is an art it seems: I wrote
backports.
You have to add backports to obtain and install 3.0.4. to Stretch.
See
https://backports.debian.org/Instructions/ if you really do not understand how to do that!
It is quite
essential Debian Linux
knowledge and I - and others - already explained it many times on this forum....
Bottom line is
you should not use 3.0.0 for
new features as currently in the 3.0.4 manuals. Or you should not use those features.
BTW you would soon have the same problem with even more new features after 3.2.0 is released....
But then again, you can bootstrap an svn checkout of 3.2.0 since you have the right starting compiler after you added backports: 3.0.4..
Or use
fpcdeluxe one time. For noobs that is the better option if you really do not understand backports.
The advantage of backports over fpcdeluxe is that it is a true Debian supported distribution of Freepascal and built by Debian maintainers.
Debian purists consider it probably essential...But if you want to be really up-to-date, use fpcdeluxe and choose 3.2.0 if you do not use FPC commercially.
Adventurers like me also install trunk separately...