Stop using gtk-doc, and switch to gi-docgen.
The gi-docgen tool generates API references through the introspection
data, which has various benefits:
- it does not parse C code
- it does not generate and run C code to introspect types at build time
- it does not present a different API from the one we're exporting
Additionally, gi-docgen:
- does not generate DocBook XML in order to generate HTML
- does not go through xsltproc
- parses proper Markdown
Which makes it markedly faster than gtk-doc has ever been.
100% symbol docs coverage.
833 symbols documented.
0 symbols incomplete.
0 not documented.
What's left are just type system macros and windowing system opaque
structures.
First of all, we must list *all* ignored headers. Since we have public
headers in the x11 and wayland directories, we must explicitly declare
all headers that we consider private under those directories.
The "quartz" subdirectory was renamed "macos", with the new macOS
backend. The "mir" directory was removed, so there's no need to ignore
it.
We are also missing a bunch of ignored headers in the top-level gdk
directory.
Finally, pass the list of ignored files to gtkdoc-mkdb, so we won't get
missing declaration warnings.
The 'documentation' option also guarded the man page build. Instead
if skipping the whole docs subdir skip the specific gtkdoc calls, so that the
man page build still works.
This brings it in line with the gtk3 meson build.
Unconditionally putting 'gdkwayland_inc' in src_dir argument of gtkdoc
call tells gtkdoc-scan to scan source files in a non-existent build
directory, gdk/wayland. To avoid causing build failure when a specific
backend is disabled, we should include directories conditionally.
We need to reference the types file directly, because it won't be copied
into the builddir by Meson — except for GTK, which needs to generate its
own types file using configure_file().
