[dconf] Allow manpages to be build seperate from gtk-doc.

[Philip Withnall <pwithnall src gnome org>]

commit ddd245227eb8459587e87a79fa06e8aaea0dabba
Author: Koop Mast <kwm rainbow-runner nl>
Date:   Sat May 12 08:38:06 2018 +0200

    Allow manpages to be build seperate from gtk-doc.
    
    Move the get_option('enable-gtk-doc') to the meson.build file in docs. And
    wrap the gtk-doc code, so 'enable-man' can be used independant from gtkdoc.
    Instead of skipping the docs directory completly.
    
    Reviewed-by: Philip Withnall <withnall endlessm com>
    https://bugzilla.gnome.org/show_bug.cgi?id=794446

 docs/meson.build | 28 +++++++++++++++-------------
 meson.build      |  6 +-----
 2 files changed, 16 insertions(+), 18 deletions(-)
---
diff --git a/docs/meson.build b/docs/meson.build
index d74eedf..47f9062 100644
--- a/docs/meson.build
+++ b/docs/meson.build
@@ -1,16 +1,18 @@
-gnome.gtkdoc(
-  meson.project_name(),
-  main_xml: meson.project_name() + '-docs.xml',
-  src_dir: [
-    common_inc,
-    client_inc
-  ],
-  dependencies: libdconf_dep,
-  scan_args: '--rebuild-types',
-  gobject_typesfile: meson.project_name() + '.types',
-  install: true,
-  install_dir: join_paths(dconf_datadir, 'gtk-doc', 'html', meson.project_name())
-)
+if get_option('enable-gtk-doc')
+  gnome.gtkdoc(
+    meson.project_name(),
+    main_xml: meson.project_name() + '-docs.xml',
+    src_dir: [
+      common_inc,
+      client_inc
+    ],
+    dependencies: libdconf_dep,
+    scan_args: '--rebuild-types',
+    gobject_typesfile: meson.project_name() + '.types',
+    install: true,
+    install_dir: join_paths(dconf_datadir, 'gtk-doc', 'html', meson.project_name())
+  )
+endif
 
 if get_option('enable-man')
   xsltproc = find_program('xsltproc', required: false)
diff --git a/meson.build b/meson.build
index cddf083..d123932 100644
--- a/meson.build
+++ b/meson.build
@@ -105,9 +105,5 @@ subdir('gdbus')
 subdir('gsettings')
 subdir('client')
 subdir('bin')
-
-if get_option('enable-gtk-doc')
-  subdir('docs')
-endif
-
+subdir('docs')
 subdir('tests')