Based on fontconfig patch from Raimund Steger.

Bug 55494 - ScriptItemizeOpenType doesn't exists under Windows XP

Instead of checking for ApplicationServices.h, which is present in all
versions of MacOSX, check for CTFontRef, a CoreText basic type.

https://github.com/grigorig/ucdn

Now that we have pthread detection in configure, we don't need Glib
anymore.  Glib will only be a Unicode data provider.

Import PortableFontInstance and add shaper stub.

Check for upstream-provided 'icu-uc' pkgconfig package.

A *real* release this time, with NEWS, ChangeLog, etc.

Apparently even that doesn't make check-internal-symbols.sh happy with
mingw32.  Going to disable that for DLLs again, but hopefully the
export-file is doing *something*.

Choose using shaper name "old".

Does not attempt to handle clusters in a Uniscribe- or HarfBuzz-compatible way;
just returns the original string indexes that CT maintains. These may even be
out-of-order in the case of reordrant glyphs.

Until I figure out the build issues.  Sigh...