application execution recorder, player and debugger

 rr allows application executions to be recorded and then replayed
 with gdb as many times as desired.
 .
 This allows intermittent, or complex to reproduce, bugs to be
 captured and then debugged at leisure. Replays are deterministic,
 always identical from one run to another.
 .
 rr is incompatible with ptrace hardening, and currently only supports
 Intel CPUs with Nehalem or later microarchitectures.