Gnome3 dependencies need Python 2.7 at most, but 3.6 was specified

[bob prohaska]

In trying to compile gnome3 from ports on a Raspberry Pi 2  error messages
with the general form:

 py27-cairo-1.10.0_2 needs Python 2.7 at most, but 3.6 was specified 

come up for numerous dependencies. The failed builds have so far successed when
done in the port directory, using make -DBATCH

The ports tree is at:
 # svnlite info /usr/ports
Path: /usr/ports
Working Copy Root Path: /usr/ports
URL: svn://svn.freebsd.org/ports/head
Relative URL: ^/head
Repository Root: svn://svn.freebsd.org/ports
Repository UUID: 35697150-7ecd-e111-bb59-0022644237b5
Revision: 445408
Node Kind: directory
Schedule: normal
Last Changed Author: lme
Last Changed Rev: 445408
Last Changed Date: 2017-07-09 12:14:55 -0700 (Sun, 09 Jul 2017)

Is there an alternative to manually compiling the failing dependencies?

thanks for reading!

bob prohaska