* Resolves an issue introduced in #5111, which inadvertently removed the
-Wno-maybe-uninitialized compiler option from some xrpl.libxrpl
modules. This resulted in new "may be used uninitialized" build
warnings, first noticed in the "protocol" module. When compiling with
derr=TRUE, those warnings became errors, which made the build fail.
* Github CI actions will build with the assert and werr options turned
on. This will cause CI jobs to fail if a developer introduces a new
compiler warning, or causes an assert to fail in release builds.
* Includes the OS and compiler version in the linux dependencies jobs in
the "check environment" step.
* Translates the `unity` build option into `CMAKE_UNITY_BUILD` setting.
* Copy Antithesis SDK version 0.4.0 to directory external/
* Add build option `voidstar` to enable instrumentation with Antithesis SDK
* Define instrumentation macros ASSERT and UNREACHABLE in terms of regular C assert
* Replace asserts with named ASSERT or UNREACHABLE
* Add UNREACHABLE to LogicError
* Document instrumentation macros in CONTRIBUTING.md
