[grilo-plugins] Add option to disable bulding help

[Victor Toso <victortoso src gnome org>]

commit 016449aa995c2244f337aeee04afc7ac5b34fd9d
Author: Victor Toso <victortoso redhat com>
Date:   Fri Jul 24 23:50:20 2020 +0200

    Add option to disable bulding help
    
    Help is meant to be a set of examples to application developers who
    are interested in using grilo-plugins in their applications.
    
    This patch addes a build option to not build and install those files
    files (only one, using TMDB, but it installs it once per LINGUAS/* at
    least. This is not needed in a sandboxed application like Flatpak
    
    Closes: https://gitlab.gnome.org/GNOME/grilo-plugins/-/issues/13

 meson.build       | 4 +++-
 meson_options.txt | 1 +
 2 files changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 30d38d64..6a037785 100644
--- a/meson.build
+++ b/meson.build
@@ -190,7 +190,9 @@ gnome = import('gnome')
 rootdir = include_directories('.')
 
 subdir('src')
-subdir('help')
+if get_option('help') != 'no'
+  subdir('help')
+endif
 subdir('po')
 subdir('tests')
 
diff --git a/meson_options.txt b/meson_options.txt
index 71f80b87..141201f0 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -21,3 +21,4 @@ option('enable-tmdb', type: 'combo', choices: [ 'auto', 'yes', 'no' ], value: 'a
 option('enable-tracker', type: 'combo', choices: [ 'auto', 'yes', 'no' ], value: 'auto', description: 
'Enable Tracker plugin (DEPRECATED)')
 option('enable-tracker3', type: 'combo', choices: [ 'auto', 'yes', 'no' ], value: 'auto', description: 
'Enable Tracker3 plugin')
 option('enable-youtube', type: 'combo', choices: [ 'auto', 'yes', 'no' ], value: 'auto', description: 
'Enable YouTube plugin')
+option('help', type: 'combo', choices: [ 'auto', 'yes', 'no' ], value: 'auto', description: 'Build examples 
developers')