Probably we should actually follow GLibs requirements and use `pkg-config`? [This seems appropriate](https://stackoverflow.com/questions/1732822/portably-include-glib-headers-in...):
By using the `PKG_CHECK_MODULES` macro, Autoconf-generated configure scripts can retrieve pkg-config data automatically. […]
PKG_CHECK_MODULES([DEPS], [glib-2.0 >= 2.24.1])
Or step by step: https://stackoverflow.com/a/14828132
However, these all assume automake, but we dont use that. I'll have a look…