const golang.org/x/sys/unix.ENOPROTOOPT

one use

	golang.org/x/sys/unix (current package)
		zerrors_linux_amd64.go#L591: 	ENOPROTOOPT     = syscall.Errno(0x5c)

The pages are generated with Golds v0.4.9. (GOOS=linux GOARCH=amd64)