This is so dumb, we can just insert C for you without you having to know
that you're using C under the hood. This is nicer because:
1) Meson doesn't make the user add a language they're not explicitly
using
2) If there was ever an implementaiton of Vala that didn't use C as
it's assembly language, this wouldn't make any sense.
The build level shouldn't be deal with interpreter objects, by the time
they leave the intpreter they should be in the Meson middle layer
representaiton
We need to konw on rconfigure which options have already bee set not
just for the super project, but also for the subproject. However, using
first_invocation is not sufficient, as a reconfigure could add a new
subpproject that wasn't present before, and we need to initialize that
project's builtins.
Dylan Baker
Xavier Claessens
Jussi Pakkanen