std: Convert statics to constants

This commit repurposes most statics as constants in the standard library itself,
with the exception of TLS keys which precisely have their own memory location as
an implementation detail.

This commit also rewrites the bitflags syntax to use `const` instead of
`static`. All invocations will need to replace the word `static` with `const`
when declaring flags.

Due to the modification of the `bitflags!` syntax, this is a:

[breaking-change]

0 files changed, 0 insertions, 0 deletions