With 12 uses of `JoinStrings` in the codebase vs 36 uses of `fmt::join`, fmtlib's range adapter for string concatenation with delimiters is clearly the preferred option.

Android interprets char as unsigned char, so comparing with 0 triggers a
tautological-unsigned-char-zero-compare warning.

Casting c to an unsigned char and removing the comparison with 0
resolves the warning while needing one less comparison on all platforms.

Now superseded by Common::FromChars

Obsoletes these functions in favor of the standard member functions
added in C++20.

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.