Thanks for digging into this.

On Jun 2, 2014 10:01 AM, "Jun T." <takimoto-j@kba.biglobe.ne.jp> wrote:
>
> The results so far suggest that readdir() output must be always converted
> to NFC on Mac.
> On Linux (and maybe on Windows) no conversion is possible because iconv()
> doesn't support UTF-8-MAC, but conversion is not necessary except for when
> mounting Mac volume via NFS.

I did some quick research into UTF-8-MAC and it appears that it's the same
as "standard" NFD except that it does NOT decompose a few specific
character ranges.  That may mean that it is possible to convert it by
passing a different source character set name to iconv, but I didn't get as
far as finding out which one to try.

However, applying iconv to every filename read from any source just because
it might be a Mac NFS mount seems like a waste of effort ...