cmd/cgo: support other GOARCH values in 1.15 [1.15 backport] #41871
Description
This is a request to add https://golang.org/cl/260657 to 1.15. This will help adding gccgo support in golang.org/x/sys/unix for architectures that are supported by gccgo but not gc.
cmd/cgo: add more architectures to size maps
This brings over the architectures that the gofrontend knows about.
This permits using the main cgo tool for those architectures,
as cgo can be used with -godefs without gc support.
This will help add golang.org/x/sys/unix support for other architectures.
For #37443