2.66.7 (stable):

Gio:
* content_type_guess(): Remove most of an unnecessary overload
  (Kjell Ahlstedt) Issue #118 (LinuxUser GD)

Documentation:
* Gio::File: Fix various spelling errors
  (Daniel Boles)
* Remove AUTHORS and README.SUN; add info to README.md
  (Kjell Ahlstedt) Issue gtkmm#140

gmmproc:
* enum.pl, enumextract.py: Accept XXX = YYY + 1
* h2def.py: Make return types that are unsigned work.
  Required by gtkmm4, GdkDmabufTextureBuilder
  (Kjell Ahlstedt)

Tests:
* Giomm tests: Test for /etc/passwd instead of /etc/fstab
  (Jeremy Bicha) Merge request !60

Build:
* Meson build: Don't fail if warning_level=everything
  (Daniel Boles, Kjell Ahlstedt) Merge request gtkmm!87
* MSVC, NMake: Make dep paths configurable
  (Chun-wei Fan)