runtime  

This categorization is based on the context that the issue arises during unit testing (specifically `check-unit`) after adding a dependency (`socat`), and it affects an ARM MacOS build. It suggests a runtime environment problem, possibly linked to the interaction with system resources or compatibility issues specific to that architecture/build setup. The failure isn't due to incorrect instructions in code nor directly related to syscall errors but rather to conditions present during execution on that particular platform.