Well, the entire c++ library on the buildbot would have to be rebuilt against libgcc's libstdc++ for this to work -- all of octave's deps and deps of deps would need to be built the same as octave, of course, and so everything else too. The whole machine has to be configured the same way (which is why intel appears to have funded the libgcc extensions when some linux distros went with defaulting to libgcc5+, making clang/llvm non-functional on those distros until they fixed it).
In the end, you would seem to wind up in a similar situation as we're in now with libc++ on these older machines. I guess I'm struggling with the benefit of doing this over either fixing the metadata problem in archives and hosting libc++ files on the buildbots, or just defaulting to libc++ on these older machines if we're ready for that.
