RFR: 8262366: Update glib to version 2.66.7 [v2]

[Alexander Matveev]

> - GLib was updated to version 2.66.7 and GStreamer to version 1.18.3
>  - One bug was discovered in updated GStreamer which was causing deadlock or infinite loop during seek on macOS. See gstsystemclock.c for changes between ifdef GSTREAMER_LITE. Otherwise no changes.

Alexander Matveev has updated the pull request incrementally with one additional commit since the last revision:

  Updated .md files and added missing include files

-------------

Changes:
  - all: https://git.openjdk.java.net/jfx/pull/447/files
  - new: https://git.openjdk.java.net/jfx/pull/447/files/341eb765..77640795

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jfx&pr=447&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jfx&pr=447&range=00-01

  Stats: 14 lines in 4 files changed: 8 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/jfx/pull/447.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/447/head:pull/447

PR: https://git.openjdk.java.net/jfx/pull/447