This needs to be built from the top makefile, for example :

  make dev/haring/haring

If HAProxy is built with special options such -DDEBUG_THREAD or with
multi-threading support enabled (which changes the ring's header size),
it can be worth reusing the same build options for haring, usually they
will remain compatible, and will simplify the handling of different file
layouts, at the expense of dragging more dependencies into the executable.