#1196

Per https://github.com/Alexpux/MSYS2-packages/issues/163#issuecomment-73555971

As it may cause a race unrelated to the issue actually happened

As https://github.com/Alexpux/MSYS2-packages/issues/702

Using a hack...

text-rendering-tests test MORX-32 shows that for Insertion, an unset mark is treated
as mark set at 0.  This is unlike the Reordering lookup where un unset mark performs
nothing.

Fixes MORX-32.

Makes MORX-29, MORX-30, MORX-31 pass.

To help TSan.

A single find_package(harfbuzz) line in user code resulted in this loop
getting stuck when _harfbuzz_libdir_iter became "/".

See comment.

What were you thinking? ;)

To match FreeType units, such that FreeType gets correct size from us.
This matters more now that we allow setting --ft-load-flags.

Fixes https://github.com/harfbuzz/harfbuzz/pull/1179

Fixes https://github.com/harfbuzz/harfbuzz/issues/1175

Now I wonder if any bots will be unhappy we calling | in static const initializations...
Or would that cost runtime init?  Our tests don't detect any..