Problem building mate port

[Montgomery-Smith, Stephen]

When I build straight from ports:
cd /usr/ports/x11/mate && make install clean

I get error messages like this:
===>  gnome-doc-utils-0.20.10_4 needs Python 2.7 at most, but 3.6 was
specified.
*** Error code 1

If I do this:
cd /usr/ports/textproc/gnome-doc-utils && make install
it works just fine.  So somehow, when textproc/gnome-doc-utils is built 
as a dependency of mate, the PYTHON variable is incorrectly set.

I had this same problem several months ago, so it is an old issue. 
Presumably most people build their ports using one of those scripts that 
build the dependency ports separately, and maybe this is why this 
problem hasn't been observed or fixed.

Thanks, Stephen