[Libguestfs] where to create localenv?

I don't want prefix 'git' and I watched this http://libguestfs.org/guestfs-building.1.html#local-files . localenv ./autogen.sh \ -C \ --enable-werror \ "$@" but I cannot execute . localenv and I saw Note that *localenv* is included by the top Makefile (so it’s a Makefile fragment). But if it is also sourced by your *localconfigure* script then it is used as a shell script. But I don't see any file named localenv after execute cmds and make: how to solve it?