[totem-pl-parser] build: Add an option for generating the API reference

[Emmanuele Bassi <ebassi src gnome org>]

commit bbac57454c0e6396f63111e0767f57476bd41a5f
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Jun 8 18:47:35 2017 +0100

    build: Add an option for generating the API reference
    
    The Autotools build generated the API reference only on demand, with the
    default setting being "off". We need the equivalent for Meson.

 meson.build       |    4 +++-
 meson_options.txt |    2 ++
 2 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/meson.build b/meson.build
index 1ad2002..d6f265b 100644
--- a/meson.build
+++ b/meson.build
@@ -236,8 +236,10 @@ plparser_inc = include_directories('plparse')
 
 subdir('lib')
 subdir('plparse')
-subdir('docs/reference')
 subdir('po')
+if get_option('enable-gtk-doc')
+  subdir('docs/reference')
+endif
 
 # config.h
 configure_file(output: 'config.h', configuration: cdata)
diff --git a/meson_options.txt b/meson_options.txt
index b212221..00f66a3 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -8,3 +8,5 @@ option('enable-libgcrypt', type: 'combo', choices : ['yes', 'no', 'auto'], value
   description : 'Enable libgcrypt support.')
 option('enable-uninstalled-tests', type: 'boolean', value: 'false',
   description : 'Enable uninstalled tests.')
+option('enable-gtk-doc', type: 'boolean', value: 'false',
+  description : 'Generate the API reference (depends on GTK-Doc)')