Are the build-arch and build-indep targets required?

[Ferenc Wagner <wferi@niif.hu>]

Hi,

https://www.debian.org/doc/debian-policy/ch-source.html#s-debianrules
first says yes, by starting a paragraph as:

    build-arch (required), build-indep (required)

but a couple of paragraphs later is also says:

    Both binary-* targets should depend on the build target, or on the
    appropriate build-arch or build-indep target, *if provided*, [...]

(emphasis mine) which implies that build-{arch,indep} may not be
provided after all, that is, they are not required.

So, what is the right interpretation of the above?  Are they required or
not?
-- 
Thanks,
Feri.