[metacity] build: enable subdir-objects

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 02c7f679a8222a32a5a3e6e2f8e91176da387db5
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sun Mar 11 13:07:19 2018 +0200

    build: enable subdir-objects

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 9ec8164..821fc58 100644
--- a/configure.ac
+++ b/configure.ac
@@ -46,7 +46,7 @@ dnl **************************************************************************
 dnl Initialize automake
 dnl **************************************************************************
 
-AM_INIT_AUTOMAKE([1.13 no-dist-gzip dist-xz tar-ustar -Wno-portability])
+AM_INIT_AUTOMAKE([1.14 no-dist-gzip dist-xz tar-ustar -Wno-portability subdir-objects])
 AM_MAINTAINER_MODE([enable])
 AM_SILENT_RULES([yes])