I require Polish diacritics, such as ą, ć, ę, etc.
Of course, I can always pre-process the file to replace UTF-8 characters with escaped characters but that's not elegant.
As of today, macOS Mojave ships with a quite outdated version of
groff (1.19 or something...) which apparently cannot handle the
-K option. Thus it fails to recognise any fancy diacritics (german umlauts in my case), if you run
groff -Kutf8 ....
You can get a newer version of groff on macOS by installing it via Homebrew, as per this post
brew install groff gs
(not sure if
gs for ghostscript is actually required; I installed it anyway)
The following convoluted way works:
groff -Kutf8 -Tdvi -mec -ms test.ms > test.dvi dvipdfm -cz 9 test.dvi open test.pdf
Via the [Groff] latin2 polish special characters thread on lists.gnu.org.