I'm not sure why this is needed, but if the dist_man_MANS
variable is not copied from the top-level Makefile down to the
man-po one then make dist from a clean archive will not work.
I'm sure someone with better automake magic than me can make
this more elegant but for now it works if a little ugly.
References:
https://www.freelists.org/post/procps/important-newlib-patches,8
79949b18ef