build: Fix running autogen.sh out-of-tree

autogen.sh

@@ -1,4 +1,10 @@
 #!/bin/sh
+
+srcdir=`dirname $0`
+test -z "$srcdir" && srcdir=.
+
+pushd $srcdir
+
 aclocal || exit 1
 autoheader || exit 1
 glib-gettextize -f -c || exit 1
@@ -7,6 +13,8 @@ intltoolize -c -f || exit 1
 libtoolize -c || exit 1
 autoconf || exit 1
 automake -a -c || exit 1
+popd
+
 if test -z "$NOCONFIGURE"; then
-	./configure $*
+	$srcdir/configure --enable-maintainer-mode $*
 fi