[gnome-shell] build: Yield 'man' option to extension-tool subproject

[Florian Müllner <fmuellner src gnome org>]

commit 8f851e8adf41684f629508876c94fc28b6b0b63d
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Mar 5 03:54:23 2020 +0100

    build: Yield 'man' option to extension-tool subproject
    
    Turns out meson has a build-in pattern of what we are doing, namely:
    Set a subproject option to a parent project option of the same name.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1072

 meson.build                                   | 1 -
 subprojects/extensions-tool/meson_options.txt | 3 ++-
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/meson.build b/meson.build
index 680b189e0b..f9e178673a 100644
--- a/meson.build
+++ b/meson.build
@@ -246,7 +246,6 @@ libgvc_gir = libgvc.get_variable('libgvc_gir')
 if get_option('extensions_tool')
   extension_tool = subproject('extensions-tool',
     default_options: [
-      'man=@0@'.format(get_option('man')),
       'package_name=@0@'.format(meson.project_name()),
     ]
   )
diff --git a/subprojects/extensions-tool/meson_options.txt b/subprojects/extensions-tool/meson_options.txt
index 2b7aef6b6e..d106bf8896 100644
--- a/subprojects/extensions-tool/meson_options.txt
+++ b/subprojects/extensions-tool/meson_options.txt
@@ -1,7 +1,8 @@
 option('man',
   type: 'boolean',
   value: true,
-  description: 'Generate man pages'
+  description: 'Generate man pages',
+  yield: true,
 )
 
 option('package_name',