build: Re-enable --warn-all for g-ir-scanner
build: Re-enable --warn-all for g-ir-scanner

Now that I don't have to see a bunch of false positives any more, we can
finally use warnings to catch issues.

jigpu/clutter,collects/clutter,heysion/clutter-clone,heysion/clutter-clone,collects/clutter,kerrickstaley/clutter-vala,ebassi/clutter,jigpu/clutter,Distrotech/clutter,dlespiau/clutter,djdeath/clutter-android,jigpu/clutter,djdeath/clutter-multithreaded,kerrickstaley/clutter-vala,GNOME/clutter,Distrotech/clutter,djdeath/clutter-android,kerrickstaley/clutter-vala,djdeath/clutter-multithreaded,jigpu/clutter,Distrotech/clutter,collects/clutter,jigpu/clutter,GNOME/clutter,djdeath/clutter,djdeath/clutter,nobled/clutter,collects/clutter,heysion/clutter-clone,spatulasnout/clutter,djdeath/clutter-android,djdeath/clutter-multithreaded,Distrotech/clutter,Distrotech/clutter,dlespiau/clutter,spatulasnout/clutter,dlespiau/clutter,GNOME/clutter,spatulasnout/clutter,djdeath/clutter-android,djdeath/clutter,collects/clutter,ebassi/clutter,nobled/clutter,spatulasnout/clutter,djdeath/clutter,djdeath/clutter,djdeath/clutter-multithreaded,ebassi/clutter,heysion/clutter-clone,ebassi/clutter,GNOME/clutter,jigpu/clutter,kerrickstaley/clutter-vala,Distrotech/clutter,djdeath/clutter-android,spatulasnout/clutter,djdeath/clutter,GNOME/clutter,nobled/clutter,heysion/clutter-clone,ebassi/clutter