Back in 5.0 timeframe, we had set up the build system so a user building source-build could do something like this:

./build.sh /p:UseSystemLibunwind=true

To force building runtime against the system libunwind. We could also trigger runtime to fallback to its own detection/building by setting this to false explicitly. This worked mostly well because we could pick what we wanted to do at build time and use that configuration explicitly. This approach accommodated system that had a libunwind as well as when it didn't.

With ArPow, we are forcing the system libunwind unconditionally

<InnerBuildArgs>$(InnerBuildArgs) --cmakeargs -DCLR_CMAKE_USE_SYSTEM_LIBUNWIND=TRUE</InnerBuildArgs>

This breaks the cases where libunwind isn't available (eg, RHEL 8) or doesn't work right for .NET (eg, Fedora 34 arm64).

Is there some way to configure ArPow so we can control this using a build-time flag? If not, can we just delete this hardcoded value and let runtime fall back to its own detection?

cc @uweigand