I'm sorry to say I'm giving up on Dingoo official firmware development. I have been messing too long with porting libstdc++ and getting StelGOO to run. There's no fun in it for me anymore.
However, I have just released all sources
for LynGOO, StelGOO and Dingkit. I hope other coders will benefit from this and will be able to port more emulators and/or improve LynGOO and StelGOO.
One final note: Dingkit was created to work together with the mipsel-4.1.2-nopic toolchain for Linux
released by Ingenic. I think it could work with other toolchains, but it might need some modifications.