runtime: clarify error when returning unpinned pointers
With the introduction of runtime.Pinner, returning a pointer to a pinned
struct that then points to an unpinned Go pointer is correctly caught.
However, the error message remained as "cgo result has Go pointer",
which should be updated to acknowledge that Go pointers to pinned
memory are allowed.
This also updates the comments for cgoCheckArg and cgoCheckResult
to similarly clarify.
Updates #46787
Change-Id: I147bb09e87dfb70a24d6d43e4cf84e8bcc2aff48
GitHub-Last-Rev:
706facb9f2bf28e1f6e575b7626f8feeca1187cf
GitHub-Pull-Request: golang/go#62606
Reviewed-on: https://go-review.googlesource.com/c/go/+/527702
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>