Vala: Add missing FeatureNew() when C is missing
Vala: Add missing FeatureNew() when C is missing

It was previously an hard error, only permitted since 0.59.0.

pexip/meson,pexip/meson,pexip/meson,pexip/meson,pexip/meson,mesonbuild/meson,jpakkane/meson,jpakkane/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,mesonbuild/meson,pexip/meson,jpakkane/meson,pexip/meson,jpakkane/meson,mesonbuild/meson,mesonbuild/meson,jpakkane/meson,jpakkane/meson,jpakkane/meson,jpakkane/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,mesonbuild/meson,mesonbuild/meson,jpakkane/meson,pexip/meson