Cross debugging

There are some scenarios where the user who is intended to debug some program isn't the one who submits the JCL. Among other situations, this happens when the job is launched from ControlM. In this case, the principal is a service user instead of the real one. We refer to that scenario as cross debugging.

Currently, this scenario isn't supported by the debugger unless the Delay Debug mode is disabled. Given that the Delay Debug mode cannot be disabled at runtime, the only way to support cross debugging is to maintain two different EQAOPTS exits with different configurations (one as the default, and an alternative version to be added to the STEPLIB on demand). This might lead to severe maintenance issues and could end up with misaligned configurations and wrong updates. Worse than that, it might require to maintain a bunch of EQAOPTS versions in order to support each combination of those configuration parameters that cannot be changed at runtime.  

So, we propose to add support to enable/disable cross debugging at runtime and decoupled from the Delay Debug mode. We suggest to support this feature by some parameter of the TEST command that can be passed to the debugger through the CEEOPTS. Alternative solutions that provide similar experience might be valid too.

Additionally, it would be nice that the Delay Debug feature and other features that cannot be enabled/disabled at runtime could.