newlocale use appears incorrect per man page; fails with Emscripten

[jason-ha]

scoped_c_thread_locale::c_locale() contains the line

*clocale = newlocale(LC_ALL, "C", nullptr);

This fails use with Emscripten (v1.39.8) as null is returned when category_mask is LC_ALL.
newlocal man page compared with _create_locale(LC_ALL, a few lines above and _create_locale docs suggest that LC_ALL_MASK is the proper category_mask argument:

*clocale = newlocale(LC_ALL_MASK, "C", nullptr);

History shows this call, once added (Steve Gates 8/28/2014), was always this way.

[BillyONeal]

I don't understand the statement that the docs page recommends LC_ALL_MASK -- neither LC_ALL_MASK nor the word mask appear on that page...

[BillyONeal]

Oh, this is for newlocale not _create_locale, I can't read.