This bug is related to #35672

I first installed oss from [community] which was broken, then tried oss-hg from AUR which was out of date, then prepared my own PKGBUILD (a 1:1 copy of oss from [community], excluding some no longer relevant patches) to build oss from git and encountered the same issue. Everything compiles but module fails to load. And then read this issue, and installed oss-nonfree. It didn't work for me either, because the old package left some stuff in /usr/lib/oss. Some date is generated (compiled?) during the first `soundon`. I guess the others were exposed to the same problem, e.g.

<kgunders> Downgrading to oss-4.2_2007-2 brings me no joy https://bugs.archlinux.org/task/35672#comment112279
<axper> There's a yet unsolved bug report for oss 4.2_2007-4, which mentions the same error message. I have downgraded to oss 4.2_2007-2, but I am still getting the same error. https://bbs.archlinux.org/viewtopic.php?pid=1291803#p1291803

While I'm generally very sceptical about using `rm -rf` in .install, in this case I would think it over if rm -rf is an option.

Given the circumstances that oss in [community] is currently broken, it's crucial people can downgrade to the previous version or oss-nonfree without problems.