[luatex] Lua interpreter difference between Windows and Mac

[Br. Samuel Springuel]

I'm writing a lua script which has the following code block:

   font_target = "greciliae.ttf"
   font_directory = kpse.find_file(font_target)
   print(font_directory)

Given that greciliae.ttf is installed in 
$TEXMFLOCAL/fonts/truetype/public/gregoriotex, the code block works fine 
on my Mac (10.11.6) when executed by texlua (and I assume on other Unix 
flavors, though I haven't tested that yet).  However, when I test the 
same code on a Windows (10) machine, font_directory ends up being nil.

When I type `kpsewhich greciliae.ttf` at the command prompt on the 
Windows machine, I get the proper path returned, so I know that 
kpsewhich can find the file.

If I switch font_target to a "gregoriotex.sty" (which is installed in 
$TEXMFLOCAL/tex/lualatex/gregoriotex/) font_directory returns the proper 
value on both machines.  Thus I know that kpse.find_file does actually 
work, at least some of the time, on Windows.

Why isn't kpse.find_file finding fonts that kpsewhich can find on 
Windows?  Am I doing something wrong?

Both machines are running version 0.95.0 (TeXLive 2016) of texlua.
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Br. Samuel, OSB
St. Anselm’s Abbey
Washington, DC
(R. Padraic Springuel)

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