cmd/cgo: fix unused parameter warnings in generated _cgo_main.c
Applying -Werror compiler option to request warnings is an usual
way to discover potential errors. Go user may put a cgo directive
in preamble: `// #cgo CFLAGS: -Werror=unused-parameter`.
However, the directive also takes effect on the cgo generated files.
I cleaned _cgo_main.c to help Go user only concentrate on warnings
of their own file.
Fixes #43639
Change-Id: I9112f02ae5226f2fc87a8650d19faee59cddd588
GitHub-Last-Rev:
f09d172f979acfba855be8108e7d79ec2778c406
GitHub-Pull-Request: golang/go#46358
Reviewed-on: https://go-review.googlesource.com/c/go/+/322232
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Bryan C. Mills <bcmills@google.com>