bug#53180: libportal missing GTK3 backend

[Liliana Marie Prikler]

Hi Guix,

this bug also affects Epiphany (build log attached).  The issue appears
to be that it tries to build without the GTK3 backend, we should
probably enable that.

Cheers

dac0xa4q6lxcp63jz3fm7phnxsn5hv-epiphany-40.3.drv.bz2
Description: application/bzip