I have WITHOUT_GIR defined (as "true") in my /etc/make.conf. All Gnome-ports seem to build fine -- whether they honor the flag or not -- except libgdata:
Couldn't find include 'Json-1.0.gir' (search path: '['/opt/share/gir-1.0', '/opt/share', '/opt/share/gir-1.0', '/usr/local/share/gir-1.0', '/usr/share/gir-1.0', '/opt/share/gir-1.0', '/usr/share/gir-1.0']')
It looks like the upstream's meson-project supports the "introspection" option, which can be set to false. The port should do that, when WITHOUT_GIR is defined.
Created attachment 227408 [details]
This gives an idea, how the problem -- with both GIR and VAPI being disabled -- may be addressed.
Only tested in the negative case, however (with WITHOUT_GIR and WITHOUT_VAPI declared in /etc/make.conf).