[ostree] configure.ac: Enable option subdir-objects for automake

[Colin Walters <walters src gnome org>]

commit a7b362998d37616ba1d8b55d498f955621ebb6cf
Author: Giuseppe Scrivano <gscrivan redhat com>
Date:   Mon Feb 2 13:00:32 2015 +0100

    configure.ac: Enable option subdir-objects for automake
    
    It silences an automake warning and keep the rootdir cleaner.
    
    Signed-off-by: Giuseppe Scrivano <gscrivan redhat com>

 configure.ac |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 4fe6d56..89eaa39 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4,7 +4,8 @@ AC_CONFIG_HEADER([config.h])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_AUX_DIR([build-aux])
 
-AM_INIT_AUTOMAKE([1.13 -Wno-portability foreign no-define tar-ustar no-dist-gzip dist-xz color-tests 
parallel-tests])
+AM_INIT_AUTOMAKE([1.13 -Wno-portability foreign no-define tar-ustar no-dist-gzip dist-xz
+                  color-tests parallel-tests subdir-objects])
 AM_MAINTAINER_MODE([enable])
 AM_SILENT_RULES([yes])
 AC_USE_SYSTEM_EXTENSIONS