to get seccomp state for checkpoint restore.
added in linux commit 26500475ac1b499d8636ff281311d633909f5d20
struct tag follows the glibc api and ptrace_peeksiginfo_args
got changed too accordingly.
allows a ptracer process to disable/enable seccomp filters of the
traced process, useful for checkpoint/restore, new in v4.3 commit
13c4a90119d28cfcb6b5bdd820c233b86c2b0237