bug#54098: 29.0.50; Unexec build broken

[Po Lu]

Po Lu <luangruo@yahoo.com> writes:

> I get:
>
> In titdic-convert:
> international/titdic-cnv.el:473:2: Error: Attempt to modify read-only object: 
> (generic dispatches-left methods)
> international/titdic-cnv.el:473:2: Error: Invalid function: "
> In titdic-convert:
> international/titdic-cnv.el:473:2: Error: Attempt to modify read-only object: 
> (generic dispatches-left methods)"
> Makefile:328: recipe for target
> 'c:/emacs/emacs-29.0.50/lisp/international/titdic-cnv.elc' failed
>
> When trying to build an unexec build, where, presumably, some more
> things in pure space are read only.
>
> Thanks.

The problem is that `byte-run-strip-symbol-positions' can modify forms
which are in pure space.

It should return a copy of the form instead, but I don't know if the
rest of the byte compiler relies on the side effects symbol position
stripping.

Alan, WDYT?