I’m posting this here both to help someone else looking for this and to check if I got everything right.
I needed to use enums in a GObject property. So I needed a enum type for my property param spec. I thought I could hard-code it somehow, but after some long time pondering (actually knocking my head into the wall) I decided to integrate glib-mkenums into autoconf so that it could generate the types for me automatically when running make from my C sources. Unfortunately for me, Google wasn’t being friendly when searching for information on glib-mkenums.
I found somewhere, some program that used glib-mkenums in a simple way (sorry, I forgot where I fount it), close to what I had in mind, so I decided to adapt it to my needs. What I had to do was to add two more files, automatically generated (in this case named dmap-enums.c and dmap-enums.h) adding some commands to Makefile.am (linked to Gitorious because WordPress removes all formatting). Hopefully that is the right way to do it, at least it is working for me.