openbsd requires specifying the path for the [`find`][0] command. So this: find -name \*.o find: unknown option -- n usage: find [-dHhLXx] [-f path] path ... [expression] fails. This works: find . -name \*.o ./dist/build/Utility/Applicative.o ./dist/build/Utility/PosixFiles.o ./dist/build/Utility/Split.o ... as expected. Here's a patch for it: [0001-Makefile-Update-clean.patch][1]. [0]: https://man.openbsd.org/find [1]: https://ricketyspace.net/patch/0001-Makefile-Update-clean.patch