PR go/68072
    cmd/cgo: ignore vars with no name or type if they have a AttrSpecification
    
    Backport of master CL https://golang.org/cl/17151.
    
    Fixes https://gcc.gnu.org/PR/68072.
    
    Reviewed-on: https://go-review.googlesource.com/17152

From-SVN: r230685