Enhance wait status decoding

* xlat/ptrace_events.in: New file.
* wait.c: Include "xlat/ptrace_events.h".
(printstatus): In case of WIFSTOPPED, print 0x80 flag separately from
the stop signal name.
[WIFCONTINUED]: Add WIFCONTINUED support.
Decode PTRACE_EVENT_* events.
2 files changed