[valadoc] build: Enable maintainer-mode by default

[Rico Tzschichholz <ricotz src gnome org>]

commit cd9b2db1d8eba2ad3bb726ec29d2a28747729b55
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Thu Jan 16 19:34:27 2014 +0100

    build: Enable maintainer-mode by default

 configure.ac |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 5d2b7a5..b8ca0f3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -11,8 +11,7 @@ AC_CONFIG_HEADERS(config.h)
 AC_CONFIG_SRCDIR([configure.ac])
 AM_INIT_AUTOMAKE([1.11 foreign tar-ustar dist-xz no-dist-gzip subdir-objects])
 
-AM_MAINTAINER_MODE
-
+AM_MAINTAINER_MODE([enable])
 
 AC_PROG_CC
 AC_PROG_INSTALL