It would be awesome if you could add libconfig. It's a rather advanced and easy to use library for human-friendly configuration files. It's one of the most popular too. http://www.hyperrealm.com/libconfig/
I already tried to port it, and I succeeded to compile everything but the resulting library did not run on the PSP. I'm not sure how much would be involved in a port, but the PS2 port of the library didn't change much at all (I ran a diff).