#738 Impnotes slightly misleading regarding Unix namestring contents
The implementation notes (section 19.3) say that for Unix pathname namestrings "Name and type may be STRINGs of any LENGTH (consisting of printing CHARACTERs, except "/")".
The documentation might be said not to describe all Clisp builds: the character repertoire that may occur in a Unix namestring turns out to be the set of characters whose encoding under CUSTOM::DEFAULT-FILE-ENCODING contains octets satisfying the expression VALID_FILENAME_CHAR in config.h.
(What might be a separate issue is that for reasons I haven't figured out, on one OSX host where I've built Clisp without any specific configure options or config.h editing, VALID_FILENAME_CHAR excludes octets above #d127, even though the resulting Clisp supports the Unicode character set. Is there any reason for VALID_FILENAME_CHAR to do this when building a Clisp with Unicode characters?)
