Inventory 0.1 is unsound (allows std access before init of Rust runtime)

[dtolnay]

I am reporting this against inventory even though the affected unsafe code lives in the ctor crate. I believe the majority of usages of ctor use it soundly. In fact inventory 0.2, which uses the same version of ctor as inventory 0.1, uses it in a manner that is not affected by this bug.

• Relevant standard library issue: Consider documenting that (parts of?) stdlib must not be used before/after main rust-lang/rust#110708
• Relevant inventory PR: Require inventory element type to be const constructed dtolnay/inventory#43

[amousset]

Thanks!