Add blank lines after //sys comments where needed, and then run gofmt
on the syscall package with the new formatter.
This is the libgo version of CL 407136.
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/412074
PR go/89447
syscall, internal/syscall: adjust use of largefile functions
Consistently call __go_openat for openat. Use fstatat64, creat64,
sendfile64, and getdents64 where needed.
Based on patch by Rainer Orth.
Fixes https://gcc.gnu.org/PR89447
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/166420
From-SVN: r269521