As you've discovered, not all file systems support the d_type
optimization.  The situation is even worse on other systems.  I
wouldn't call this a hack--it's simply what you have to do when the
file system doesn't support d_type.  There really isn't another
option.

I don't think this approach is any racier than relying on d_type.
There will always be TOCTOU races unless you open the file first
and use fstat().  That's true whether you get the info from readdir(2)
or lstat(2).

What you have there looks fine to me, though I would remove the
comment about it being racey.

 - todd