offline docs by default.

data/meson.build

@@ -6,4 +6,29 @@ if get_option('gtk-frontend')
   subdir('icons')
   subdir('misc')
   subdir('man')
+
+  # Fetch and build the offline manual so Help->Contents works without
+  # connectivity. 'auto' skips with a warning when the docs cannot be
+  # fetched (e.g. network-less distro builds, which ship docs themselves);
+  # 'enabled' makes that a hard error.
+  offline_docs_opt = get_option('offline-docs')
+  if not offline_docs_opt.disabled()
+    offline_docs_args = [
+      '--repo', get_option('offline-docs-repo'),
+      '--output', join_paths(meson.current_build_dir(), 'offline-docs'),
+      '--stamp', '@OUTPUT@',
+    ]
+    if offline_docs_opt.enabled()
+      offline_docs_args += ['--strict']
+    endif
+    custom_target('offline-docs',
+      output: 'offline-docs.stamp',
+      command: [find_program('python3'), files('misc/build_offline_docs.py')] + offline_docs_args,
+      build_by_default: true,
+    )
+    meson.add_install_script(files('misc/install_offline_docs.py'),
+      join_paths(meson.current_build_dir(), 'offline-docs'),
+      offline_docs_dir,
+    )
+  endif
 endif