[HarfBuzz] harfbuzz: Changes to 'overload-overload'

[Behdad Esfahbod]

New branch 'overload-overload' available with the following commits:
commit db56d481cdfe848240d0f009656d290cf7e63d14
Author: Behdad Esfahbod <behdad at behdad.org>
Date:   Fri Nov 30 19:49:03 2018 -0500

    Another approach to fixing pesky-gcc's ambiguous overload overload

commit 51977fb38f73ea3ef9ae436353208de828ec6141
Author: Behdad Esfahbod <behdad at behdad.org>
Date:   Fri Nov 30 19:47:11 2018 -0500

    Break pesky-gcc build