Dear all,

the attached patch fixes a long-standing issue with CLASS attributes
when a declaration is scattered over multiple statements.

The major part ("draft") of the patch is by Tobias, which I took up
before it started to bit-rot too much, see PR.  It is mainly about
a proper updating and book-keeping of symbol attributes.

While debugging the draft patch, I fixed a few disturbing memleaks
in class.cc that showed up when looking at intermediate fallout.

This patch also addresses issues reported in a few other PRs:
pr53951, pr101101, pr104229, pr107380.  These are mostly
duplicates at some level.

Regtested on x86_64-pc-linux-gnu.  OK for mainline?

Thanks,
Harald