4.0.3 (stable):

Documentation:
* Update Visual Studio build docs
  (Chun-wei Fan) Pull request #56
* Parser docs: Add a link to parser options
  (Kjell Ahlstedt)

Meson build:
* Detect if we build from a git subtree
  (William Roy) Merge request gtkmm!72
* Don't copy files with configure_file()
  (Kjell Ahlstedt)
* Fix the evaluation of is_git_build on Windows
  (Kjell Ahlstedt) Issue gtkmm#131 (William Roy)
* Backport libxml2 CMake support from libxml++-5.0
  (Chun-wei Fan) Pull request #55
* Don't fail if warning_level=everything
  (Daniel Boles, Kjell Ahlstedt) Merge request gtkmm!87
* Don't require the 'dot' command to build the documentation
  (Kjell Ahlstedt) Issue libsigcplusplus#98
* Add the build-manual option
  (Kjell Ahlstedt)
* Add bcrypt dependency when libxml2 is a subproject
  Issue #64 (Kjell Ahlstedt)
  (Andrew Potter) Pull request #65

Build:
* Make it compatible with libxml2 >= 2.12.0
  by modifying #include directives
  (Kjell Ahlstedt)