AFAIK it's Gnome-based, so you should be able to build FBReader there without any porting.
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Wbr,
Antony Dovgal
According to the specification, it's AMD Geode:
http://wiki.laptop.org/go/Hardware_specification
There is no much info on the packages used though..
http://wiki.laptop.org/go/Package_management
But there is some kind of SDK available:
http://people.redhat.com/berrange/olpc/sdk/
--
Wbr,
Antony Dovgal