At work we have been making a C++ 3D engine which favours portability above all else. The technology used varies per platform (The only common part is OpenGL).
Some of the tech used for desktop platforms is Xlib/glx, libpng, openal, libogg/libvorbis.
The consumer platforms (Android / iOS) use the underlying platform's stuff but wrapped with C APIs similar to the desktop counterparts to minimize #ifdefs and other changes to the core games.
All the model loading, animation and physics is bespoke and written in C (with C++ wrappers) so is perfectly portable to everything.
To get it up to a usable state ready for games it took two of us a couple of months. It is unlikely to be as advanced as Hodgman's but as an "indie" studio, we currently need to battle with tablet / phone support and all the gimmicky short lived technology that it brings.