[HarfBuzz] Pre-base Vowel Following Cluster Used to be Rendered Afterwards

[Richard Wordingham]

This bug (https://github.com/behdad/harfbuzz/issues/180) was fixed on
17 December 2015.  It was present in at least HarfBuzz Versions 1.0.1
and 1.1.2, and was gone in Version 1.1.3.

It's been annoying me in LibreOffice for some time now.  The problem is
that I'm using a long-term-support version of Ubuntu, 16.04 Xenial.
Xenial's distribution provides Version 1.0.1 of HarfBuzz - Package
libharfbuzz0b Version 1.0.1-1ubuntu0.1 to be precise.  We can cite it
for at least two living scripts, Balinese and Tai Tham (for Tai
Khuen - example string is ᩉ᩠ᩅᩯᩁ /wɛːn/ 'ring (n.)').

Should one hope to get it fixed for Xenial?  Alternatively, should I add
a work-around to my OpenType Tai Tham font, which just about works,
despite USE.  (An alternative is for Xenial users to replace
libharfbuzz.so.0 by a newer shareable object without going through the
repositories.)

Richard.