hi,

> Should PKG_OPTIONS_LEGACY_VARS currently support converting
> NO_FOO variables to -foo options?

  It didn't, since I never thought about it.  It does now:

PKG_OPTIONS_LEGACY_VARS+=	NO_FOO:-foo

> How do we want to name package-local variables like in this case?

  I would suggest <pkgbase>-<option>, as in gqmpeg-japanese.

					yours,
					dillo