muon - meson in C

Hi!

I think some people here do not like meson because it depends on
Python and thus pulls in a couple dependencies/takes longer to build.

Other people thought so too, so they implemented a meson-like tool
called muon, written in C.

It is already packaged as devel/muon and is supposedly enough to build
e.g. devel/pkgconf.

So if you using muon instead of meson scratches an itch you have,
please test it out a bit; perhaps we can use it as a (partial?)
replacement for building meson packages (perhaps using similar
switches to CMAKE_GENERATOR/CMAKE_GENERATORS_INCOMPATIBLE).

Cheers,
 Thomas