I'm using gentoo installed from stage3-mips4-2008.0 + portage snapshot portage-20090221 on SGI O2 machine. trying to add sox to my system was unsuccessful, emerge complained about missing keyword for sox. But after manual unmasking sox-14.2.0 and gsm-1.0.12-r1 they compiles and works fine for sample rate conversion at least. So i suggest to add ~mips to these two packages.
Thanks for testing. Reassigning to mips.
Removing sound@, feel free to keyword at your leisure.
Added ~mips.