GitLab

Add seccomp ioctl numbers and newer seccomp flags necessary for the
USER_NOTIF broker.

Also adds linux_prctl.h for prctl constants like PR_SET_PTRACER.

Bug: 1117351
Change-Id: Idf56efcb189f1b20f13b23bacc71dd1b38786c4b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2407064
Commit-Queue: Matthew Denton <mpdenton@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811121}