MFC r334101:Add GET_STACK_USAGE() for arm64.
MFC r319871:Make struct syscall_args visible to userspace compilation environmentfrom machine/proc.h, consistently on all architectures.
Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.Prune svn:mergeinfo from the new branch, as nothing has been mergedhere.Additional commits post-branch will follow.Approved by: re (implicit)Sponsored by: The FreeBSD Foundation
Renumber clauses to avoid missing 3
Add the start of the arm64 machine headers. This is the subset needed tostart getting userland libraries building.Reviewed by: impSponsored by: The FreeBSD Foundation