OK... libGL shouldn't have been compiled using C++, so it shouldn't care about the libstdc++ library. It's more likely the fault of the app you're compiling...
Does tuxracer work? It is a bit of a chore to get going (it requires a bunch of stuff, including tcl, which requires tcsh -- but there's a hint somewhere at hints.linuxfromscratch.org on how to get it all working), but it should be a decent test, as it compiled fine here.
Otherwise I can try that xlockmore package, and see if I can find something.