No, but I took care not to update the base packages, but I guess I missed something. I'll just build a new version with a clean box. I don't even know how I got glib 2.12.12.
I inspected my package and the slack-required file only requires glib-2.10.3, the stock version.
The problem is the latest version gslapt is picking up is pidgin-2.1.0-i586-2vl58.tlz, the one I built is 1vl58, I have no idea where that other package came from. I also tested my package with a clean box and it works.