mozilla/rr — pull request #1124 by staktrace (2014-04-29 12:22:08+00:00)
Title: Skip past intervening frames when looking for the syscall exit frame.

Wasn't sure if you wanted peek_to to be fallible or not so I went with the signature you described. I can change it return a bool for success and take a trace_frame& out-param if you prefer.