filesystem character encoding

To the best of my knowledge, Linux is completely ignorant of pathname encoding: a file or directory just has a NUL-terminated string for a name, and whether that's encoded in UTF-8 or ASCII or ... is up to the application. (This is in contrast to the approach taken by Darwin - for example - where filenames are internally represented in a kind of weird decomposed UTF-8, regardless of the filesystem. Windows uses UTF-16; FreeBSD either uses UTF-8 or plans to standardize on that in the near future.)

Even if there's no good way for OPEN or DIRECTORY or ... to guess what encoding's in use, there should at least be a default for Linux and other OSes that don't impose or follow encoding conventions.

(Whatever that's called - perhaps *DEFAULT-PATHNAME-ENCODING* - the way that a pathname is encoded doesn't generally have anything to with how its contents are encoded.)

Maybe it's reasonable to determine default encoding by the value of LC_CTYPE or LANG.

r11200, r11202 adds some support for specifying the encoding used for filenames.