Macros that expand to include the standard define macro are undefined.
This is pretty trivial to fix. We can just do the test and then define
the name itself if it's true, rather than making the set of definition
checks the macro itself.
SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
Begins the transition to using fmt for string formatting where
applicable. Given fmt supports formatting std::string instances out of
the box, we can remove now-unnecessary calls to .c_str() and .data().
Note that this change does not touch the actual logging subsystem aside
from converting the final StringFromFormat call in the process over to
fmt::format. Given our logging system is heavily used throughout the
entire codebase, and converting that over will be quite a large change
by itself, this will be tackled near the end of the conversion process.
This makes it easier to generate random numbers or fill a buffer with
random data in a cryptographically secure way.
This also replaces existing usages of RNG functions in the codebase:
* <random> is pretty hard to use correctly, and std::random_device does
not give enough guarantees about its results (it's
implementation-defined, non cryptographically secure and could be
deterministic on some platforms).
Doing things correctly is error prone and verbose.
* rand() is terrible and should not be used especially in crypto code.
