Solved 2021Q4: editors/libreoffice does not build

The usual issues with quarterly. This time:

===>  py38-lxml-4.6.3 Unknown flavor 'py38', possible flavors: py37.
*** Error code 1

This happens when /etc/make.conf specifies a python default version which is NOT equal to the one libreoffice would prefer. Libreoffice does prefer 3.8, while I do still have 3.7 as default.

Libreoffice does promote it's preferred version to the dependencies, here py-lxml, which then should build as py38-lxml.
But, for whatever reason, the default layout of the python flavors is so that flavors other than the default python version cannot be build (except when the port defines USE_PYTHON=allflavors, which lxml doesn't). And so the above error raises.

This limitation can be switched off: set BUILD_ALL_PYTHON_FLAVORS=yes in /etc/make.conf. I did not find any further harm this option would introduce, and I do not really understand why this is not the default.

Some further discussion about the matter can be found here: