[lucida] need to manually specify bold/italic fonts with current fontspec

[Karl Berry]

    \setmainfont{LucidaBrightOT}

Does kpsewhich lucidabrightot.fontspec give you anything?
I don't see that file being read in your log. If it's not being read,
all is hopeless as far as automatic filename finding goes.

I suspect that your run is still doing system font name lookups,
hence the bold breakage. (I don't know how to solve that or who is
maintaining luaotfload these days.)

I can't imagine why being on a mac per se should make a difference.
For me, both xelatex and luatex are finding the .fontspec.

I hope Will make a new fontspec release soon to ameliorate at least some
of these discrepancies. -k