[gupnp] doc: Let meson do the build/src thing

[Jens Georg <jensgeorg src gnome org>]

commit 4a19b4ce01dc963de040743b23649a42a8bed5b8
Author: Jens Georg <mail jensge org>
Date:   Tue Oct 6 11:23:37 2020 +0200

    doc: Let meson do the build/src thing

 doc/meson.build | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/doc/meson.build b/doc/meson.build
index b71b657..26c32c9 100644
--- a/doc/meson.build
+++ b/doc/meson.build
@@ -5,10 +5,9 @@ version_xml = configure_file(input: 'version.xml.in',
                entities)
 
 if get_option('gtk_doc')
-gnome.gtkdoc('gupnp',
+    gnome.gtkdoc('gupnp',
              main_xml : 'gupnp-docs.xml',
-             src_dir : [join_paths(meson.source_root(), 'libgupnp'),
-                        join_paths(meson.build_root(), 'libgupnp')],
+             src_dir : ['libgupnp'],
              dependencies : libgupnp,
              scan_args : ['--ignore-decorators', 'G_DEPRECATED|G_GNUC_DEPRECATED,G_DEPRECATED_FOR'],
              ignore_headers : [