[tlbuild] Bug in kpse-icu-flags.m4: a long-standing OpenBSD buildfailure

[Akira Kakuto]

> As such, it'd be nice to get this into the TL'17 build. I'll see
> if I can get Behdad to push out a new harfbuzz release pronto,
> so we can merge it into the TL tree.

I have installed harfbuzz 1.4.6 in TeX Live svn.

Thanks,
Akira