[gupnp-dlna] Explicitly add AM_MAINTAINER_MODE([enable])

[Jens Georg <jensgeorg src gnome org>]

commit 4c6955146f27929b9a52d1c156fa7c3dcf0b8ce1
Author: Jens Georg <mail jensge org>
Date:   Thu Jan 31 14:08:02 2013 +0100

    Explicitly add AM_MAINTAINER_MODE([enable])

 configure.ac |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 9866c8e..6927816 100644
--- a/configure.ac
+++ b/configure.ac
@@ -11,6 +11,7 @@ AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_AUX_DIR([build-aux])
 
 AM_INIT_AUTOMAKE([1.11 tar-ustar no-dist-gzip dist-xz])
+AM_MAINTAINER_MODE([enable])
 
 AM_SILENT_RULES([yes])