Now callbacks can stop further enumeration and report errors, if they had a
catastrophic issue or just found what they needed and don't need to process
any more items.
Also, the actual enumerators can report errors instead of silently dropping
items. This led to several other fixes as all these implementations got
audited and reworked.
The original, non-callback enumerator now returns NULL if it can't produce a
complete list instead of dropping items and returning a partial list.
- Dramatically reduce RAM usage: uses between 8 and 11 kilobytes less static
memory for its internal case-folding tables.
- Actually works now. It would fail unconditionally if a codepoint folded
into multiple codepoints, even if the compared string contained those exact
codepoints.
- Now a public API!
- Removed __PHYSFS_utf8strnicmp(): nothing was using it, it was incorrect
anyhow, and what does 'n' represent when either string might case-fold to
something larger in-flight, anyhow?
So now you can drop this into your program and not worry about filename
conflicts, or where "platform_unix.c" came from in the debugger, etc.
Also renamed the "beos" sources to "haiku" and "macosx" to "macos" to match
modern platform names.