win32: better handling of nested symlinks

Our realpath(3) implementation uses xmalloc_follow_symlinks() to
expand symlinks.  This detects when symlinks are too deeply nested
but didn't set errno, so anything calling realpath(3) was unable to
say what had gone wrong.  (For example, 'ls -L' or 'stat -L'.)
Set errno to ELOOP.

This then leads to the problem that Windows doesn't know about
ELOOP so reports 'Unknown error'.  Add a replacement for strerror(3)
which returns a sensible message.

Costs 96 bytes.

0 files changed, 0 insertions, 0 deletions