[atk] build: Add option to disable introspection

[Chun-wei Fan <fanchunwei src gnome org>]

commit 271d9e4127fed5db8b85ced59ac15748e49ea287
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Tue Sep 12 12:19:37 2017 +0800

    build: Add option to disable introspection
    
    This adds an option to Meson builds to disable introspection builds even
    when GObject-Introspection is installed.  Introspection is still enabled
    by default.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=785802

 atk/meson.build   |    4 +++-
 meson_options.txt |    4 ++++
 2 files changed, 7 insertions(+), 1 deletions(-)
---
diff --git a/atk/meson.build b/atk/meson.build
index 95942e0..7b5a683 100644
--- a/atk/meson.build
+++ b/atk/meson.build
@@ -137,7 +137,9 @@ libatk_dep = declare_dependency(link_with: libatk,
                                 dependencies: gobject_dep,
                                 sources: atk_enum_h)
 
-if not meson.is_cross_build()
+disable_introspection = get_option('disable_introspection')
+
+if not meson.is_cross_build() and not disable_introspection
   gnome.generate_gir(libatk,
                      sources: atk_sources + atk_headers + [ atk_enum_h ] + [ atk_version_h ],
                      namespace: 'Atk',
diff --git a/meson_options.txt b/meson_options.txt
index 6c306f3..562a498 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -2,3 +2,7 @@ option('enable_docs',
        description: 'Build API reference for ATK using GTK-Doc',
        type: 'boolean',
        value: false)
+option('disable_introspection',
+       description: 'Do not build introspection files, even when GObject-Introspection is found',
+       type: 'boolean',
+       value: false)