I'm okay with standardizing a facade here when what underlies it is bad (like termio), but in general I'd rather standardize a low-level API so that high-level APIs (also definitely in scope) can be mostly portable rather than non-portable.  This would include things like a high-level directory API that caches the full path and file-info (stat) information lazily as it goes, a popen-ish API, and so on.

I realize that this approach won't work for JVM and CLR Schemes, but they are free to implement the higher-level stuff over what they have, and throw exceptions when low-level operations are done.  (That said, I note that there is a drop-in version of the Python "os" module for Jython at <https://sourceforge.net/projects/jnios/> which uses JNI.)