bug#42147: 28.0.50; pure vs side-effect-free, missing optimizations?

[Paul Eggert]

On 7/5/20 8:11 AM, Stefan Monnier wrote:
>> Since Emacs links to WebKit2GTK by default,
> I don't believe this is the case.

Oh, you're right. I mistakenly assumed Fedora used a default configuration, ran
"ldd /usr/bin/emacs", and saw libwebkit2gtk-4.0.so.37, so I thought WebKit2GTK
was in by default.

To get WebKit2GTK linked, one must configure Emacs with --with-xwidgets. Fedora
does that, so their x86 Emacs would require SSE2 if they still supported x86.
Which they do not - they dropped support for x86 in Fedora 31 (2019).