I've chosen a conservative setting for CPU_CLIPS_NEGATIVE/CPU_CLIPS_POSITIVE because I'm not quite sure how to determine this at build time for a cross target. This may degrade the perf of some resamplers on some machines.
Upstream picks this value by running a test program on the host machine at build time. This isn't viable here as we want to support cross compilation. I'm not sure how to determine this value for a given target, so I've set the value conservatively for now.
This is not high priority for me at the moment as I'm currently only using this library for offline processing, but contributions are welcome!