The new webkit2gtk build should in theory work with Illumos, but this should be checked on an actual Illumos/Solaris machine (bear in mind that there are enough differences between Illumos and Solaris that they count as separate platforms).
For CI there is https://github.com/vmactions/solaris-vm - perhaps this template could be used to create a version for OpenIndiana (or another Illumos distro)
The new webkit2gtk build should in theory work with Illumos, but this should be checked on an actual Illumos/Solaris machine (bear in mind that there are enough differences between Illumos and Solaris that they count as separate platforms).
For CI there is https://github.com/vmactions/solaris-vm - perhaps this template could be used to create a version for OpenIndiana (or another Illumos distro)