Update to latest pugl

[drobilla]

Minor updates for some API changes. The API changes are entirely superficial (although there are other changes in pugl), working towards more significant things.

I didn't bother forking the submodule and updating it here (seems like just busy-work), this works with current pugl main (lv2/pugl@5287bd1).

⚠️ Entirely untested aside from building ⚠️

[falkTX]

Updating the pugl submodule would be nice for doing build tests here.

I think something like this should just work

cd .../pugl-upstream
git fetch git@...lv2-remote
git checkout abcdef-lv2-remote-hash

github stores forked repos data together, so the submodule can point to a commit from a different repo and its still valid

[falkTX]

I updated to latest pugl in a1f7bc3
Your diff served nicely as a reference, thanks!