Enable -Wexit-time-destructors for all in-tree library targets and
update process-lifetime library statics so they no longer register
exit-time destructors. Long-lived caches, lookup tables, singleton
registries, and generated constants now use NeverDestroyed or leaked
references where the data is intended to live until process exit.
Update LibWeb, LibLine, and the binding generators so regenerated
sources follow the same rule instead of reintroducing destructed
statics.
These form the basis of Content Security Policy. A policy is a
collection of directives that are parsed from either the
Content-Security-Policy(-Report-Only) HTTP header, or the `<meta>`
element.
The directives are what restrict the operations can be performed in the
current global execution context. For example, "frame-ancestors: none"
tells us to prevent the page from being loaded in an embedded context,
such as `<iframe>`.
You can see it a bit like OpenBSD's pledge() functionality, but for the
web platform: https://man.openbsd.org/pledge.2
