* add kernel stack trace option to capable
Signed-off-by: Andrea Righi <andrea@betterlinux.com>

* capable: avoid stack trace overwrite

Use 0 in get_stack() to avoid overwriting the stack trace in the
kernel for the same stack_id.
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>

* capable: print both TID and PID
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>

* add user-space stack trace option to capable
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>

* capable: avoid catching itself
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>

* capable: drop unused member pid_tgid in struct
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>

* capable: report a proper error message when stack trace is missing

Print [Missed User Stack] or [Missed Kernel Stack] when get_stackid()
returns an error.
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>

* capable: add missing errno import
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>

* capable: remove dependency from python-enum module
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>