can protgroup github ahndle git submodules?

[macports at parvis.nl]

> On 2020-05-08, at 09:40, Ryan Schmidt <ryandesign at macports.org> wrote:
> 
> 
> 
> On May 6, 2020, at 06:35, macports at parvis.nl wrote:
> 
>> (still trying to make a port for hfsinspect)
>> 
>> after solving the problem with source differences due to using the wrong commit now the build errors on missing files from git submodules.
> 
> The github portgroup is documented in the guide, including this section answering this question:
> 
> https://guide.macports.org/#reference.portgroup.github.submodule

found it. thanks.