Pass information about original end position for c function arguments
processed in pointer checking generated code.
Fixes#42580
Change-Id: Ic8a578168362f0ca6055064dbbea092ad37477a6
Reviewed-on: https://go-review.googlesource.com/c/go/+/269760
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Dmitri Shuralyov <dmitshur@golang.org>