[gdk-pixbuf/doc-fixes: 5/6] Add `gtk_doc` build option

[Emmanuele Bassi <ebassi src gnome org>]

commit 716158e6dec609bc973d4242c922cdb57bbcb7ad
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Fri Jun 26 11:15:10 2020 +0100

    Add `gtk_doc` build option
    
    And deprecate the `docs` one.
    
    The `gtk_doc` option is shared across GNOME modules, so we should
    conform to the established practice.

 docs/meson.build  | 4 ++++
 meson.build       | 3 ++-
 meson_options.txt | 6 +++++-
 3 files changed, 11 insertions(+), 2 deletions(-)
---
diff --git a/docs/meson.build b/docs/meson.build
index 4615bfaad..c7c8fe721 100644
--- a/docs/meson.build
+++ b/docs/meson.build
@@ -33,6 +33,10 @@ private_headers = [
 ]
 
 if get_option('docs')
+  warning('The "docs" build option is deprecated; please use "gtk_doc=true"')
+endif
+
+if get_option('gtk_doc') or get_option('docs')
   gnome.gtkdoc('gdk-pixbuf',
                main_xml: 'gdk-pixbuf.xml',
                src_dir: [ gdk_pixbuf_inc ],
diff --git a/meson.build b/meson.build
index bd4f0dff6..8349e5f3b 100644
--- a/meson.build
+++ b/meson.build
@@ -414,6 +414,7 @@ if not meson.is_cross_build()
 endif
 
 # Documentation
+build_docs = get_option('gtk_doc') or get_option('docs')
 subdir('docs')
 
 if not meson.is_cross_build()
@@ -444,7 +445,7 @@ summary = [
   '',
   '  enabled loaders: @0@'.format(' '.join(enabled_loaders)),
   '',
-  '    documentation: @0@'.format(get_option('docs')),
+  '    documentation: @0@'.format(build_docs),
   '        man pages: @0@'.format(get_option('man')),
   '    introspection: @0@'.format(get_option('gir')),
   '  installed tests: @0@'.format(get_option('installed_tests')),
diff --git a/meson_options.txt b/meson_options.txt
index 1add5a86b..c22d29425 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -18,10 +18,14 @@ option('builtin_loaders',
        description: 'Comma-separated list of loaders to build into gdk-pixbuf, or "none", or "all" to build 
all buildable loaders into gdk-pixbuf',
        type: 'string',
        value: 'none')
-option('docs',
+option('gtk_doc',
        description: 'Whether to generate the API reference (requires GTK-Doc)',
        type: 'boolean',
        value: false)
+option('docs',
+       description: 'Whether to generate the whole documentation (see: gtk_doc and man options) 
[Deprecated]',
+       type: 'boolean',
+       value: false)
 option('gir',
        description: 'Whether to generate the API introspection data (requires GObject-Introspection)',
        type: 'boolean',