The AUR is for Arch and trying to use it on a different distro will have mixed results at best.
You can either wait for Manjaro to catch up and add the glib2-devel package which was created over a month ago, or edit the plgbuild and change it to glib2
Side by side I could pick out bad decaf, but I'd struggle to notice good decaf.
On its own I'd just assume I was given a bad to average cup of coffee, which is what I would expect anywhere but home.