I've figured out a way to use the GCC compile farm (
https://cfarm.tetaneutral.net/) with travis-ci so real hardware builds/tests can participate in the travis-ci testing process. The trick was to write a web service (
https://github.com/libffi/cfarm-test-libffi) that travis-ci will curl to for specific platforms, and it is responsible for ssh'ing into the appropriate compile farm box for testing. It seems to work well, so I've replaced the aarch64 qemu testing with real aarch64, as well as added ppc64le and mips64el linux tests. Here's some sample results:
https://travis-ci.org/libffi/libffi/builds/605684679
If anybody is willing to give me ssh access to additional gear, I'd be happy to add them to the mix.
AG