[gupnp-av] Explicitly call AM_MAINTAINER_MODE([enable])

[Jens Georg <jensgeorg src gnome org>]

commit bcb1e53b5239e77cd2333f3ab471cdb95bfc4584
Author: Jens Georg <mail jensge org>
Date:   Thu Jan 31 14:46:57 2013 +0100

    Explicitly call AM_MAINTAINER_MODE([enable])

 configure.ac |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 0347529..28661a6 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 -Wno-portability])
+AM_MAINTAINER_MODE([enable])
 
 AM_SILENT_RULES([yes])