pango: update to 1.44.3.

Switch to meson, autoconf build support was removed.

Overview of changes in 1.44.3
=============================
- Install pango-ot headers
- Make subpixel positioning optional
- fc: Ignore fonts with unsupported formats

Overview of changes in 1.44.2
=============================
- Disable ligatures when letterspacing
- Set design coords on hb_font_t
- Expose more font options in pango-view
- OS X: Make 'system-ui' font work
- Keep deprecated pango-fc apis in headers
- Make hex boxes work, always
- introspection: Various build fixes
- introspection: Add PangoPT, PangoFT2 namespaces
- layout: Make the new line-spacing opt-in

Overview of changes in 1.44.1
=============================
- Fix a crash with allow_break attributes
- Fix Emoji spacing
- Fix up includes and pkg-config requires
- Correct some cases for hyphen insertion

Overview of changes in 1.44.0
=============================
- Use harfbuzz for shaping on all platforms
- Stop using freetype for font loading; this
    drops support for type1 and bitmap fonts
- Add a getter for hb_font_t
- Make PangoCoverage a GObject
- Add a pango_tailor_break api
- font metrics: Add line height
- layout: Support line spacing
- layout: Draw hyphens for line breaks
- Add an attribute to suppress line breaking
- cairo: Don't render hex boxes for space
- Add an attribute to show invisible characters
- Stop quantizing glyph positions
- Add tests for itemization and line breaking
- Remove language and shape engine remnants
- Rename meson options: gtk_doc, introspection
- Require GLib 2.59.2
- Require Harfbuzz 2.0

Overview of changes in 1.43.0
=============================
- Drop autotools
- Drop Visual Studio build
- Build with meson everywhere
- Update Emoji tables for Unicode 11
- Update test data for Unicode 11
- Fix a crash with Thai breaking
- Fix a crash with font variations
- Deprecate bidi apis in favor of fribidi
- Add a variable font family api
- Improve font fallback handling on win32

(wiz)