make update-po is broken

Something appears borked with Makefile generation for the po directory.
When trying to update translations via:
cd po ; make update-po
we get this:
tarball/drizzle/po$ make update-po
make: *** No rule to make target `update-po'. Stop.

Contents of po directory:
ar.po de.po eu.po hu.po Makefile.in.in nl.po ro.po te.po
bn.po el.po fo.po id.po ml.po oc.po ru.po tr.po
ca.po en_AU.po fr.po it.po mr.po pl.po sk.po uk.po
cs.po en_GB.po gl.po ja.po ms.po POTFILES.in sq.po zh_CN.po
cy.po eo.po he.po ko.po mt.po pt_BR.po sv.po zh_HK.po
da.po es.po hi.po LINGUAS nb.po pt.po ta.po