[devhelp] build: improve configuration summary message

[Sébastien Wilmet <swilmet src gnome org>]

commit f229ae1d0917539f21ce5a382271ce4a2d21ed6c
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sun Apr 1 13:50:56 2018 +0200

    build: improve configuration summary message

 meson.build |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/meson.build b/meson.build
index 2901a2f..8b7d37f 100644
--- a/meson.build
+++ b/meson.build
@@ -165,5 +165,6 @@ meson.add_install_script(
 output = 'Configuration:\n\n'
 output += '        Devhelp version ' + meson.project_version() + '\n\n'
 output += '        Prefix:             ' + get_option('prefix') + '\n'
-output += '        Flatpak build mode: ' + get_option('flatpak_build').to_string()
+output += '        API documentation:  ' + get_option('gtk_doc').to_string() + '\n'
+output += '        Flatpak build mode: ' + get_option('flatpak_build').to_string() + '\n'
 message(output)