References: golang.org/x/sys/unix.RTNLGRP_IPV4

const golang.org/x/sys/unix.RTNLGRP_IPV4_MCADDR

one use

	golang.org/x/sys/unix (current package)
		ztypes_linux.go#L3121: 	RTNLGRP_IPV4_MCADDR   = 0x25

The pages are generated with Golds v0.7.6. (GOOS=linux GOARCH=amd64)