[Vala] Nice stuff incoming for the next Meson release

[Guillaume Poirier-Morency <guillaumepoiriermorency gmail com>]

There's a couple of changes on the way for the next release of Meson
(0.40.0) that will have a really good and positive aspect for people using
Vala:

   - support for multiple install directories (girdir, vapidir, includedir,
   ...)
   - support for VALAFLAGS and -Dvala_args to pass compiler arguments from
   an external source
   - arguments for specific GIR and VAPI install directory
   - better and more consistent arguments for Vala targets

If you don't use Meson yet, I strongly suggest you to consider using it and
help me making it into tier-1 language!

Related PRs:

   - https://github.com/mesonbuild/meson/pull/1469
   - https://github.com/mesonbuild/meson/pull/1599
   - https://github.com/mesonbuild/meson/pull/954
   - https://github.com/mesonbuild/meson/pull/1603
   - https://github.com/mesonbuild/meson/pull/1610

-- 
Guillaume Poirier-Morency <guillaumepoiriermorency gmail com>

Étudiant au baccalauréat en Informatique à l'Université de Montréal
Chercheur boursier à l'Institut de recherche en immunologie et en
cancérologie

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