Allow tracking parent and child at the same time on fork

[Arinerron]

• need to pass around a ctx struct and get rid of globals
• probably want to track children... maybe have a children linked list?
• have to redo analysis to support tracing exec()s too
• how to distinguish between children/processes? maybe make a global flag to show binary name every operation on fork as a prefix (to distinguish processes) and another to show process ID (to distinguish between children)
• how do we calculate the oid for separate processes/threads? it would be confusing if oids were global, but they need to be unique to support things like --break

[Arinerron]

this is complicated mainly because we have to make heaptrace itself fork to be able to waitpid both forks.

[Arinerron]

ok nvm apparently you can waitpid() process groups lets gooo