build: enable the 'subdir-objects' Automake option globally

This is not strictly required now (it will be once we make more
parts of the coreutils build system non-recursive), but enabling
it early helps to ensure that we don't unwittingly introduce any
incompatibility or subtle breakage later.

* configure.ac (AM_INIT_AUTOMAKE): Add  'subdir-objects'.

diff --git a/configure.ac b/configure.ac
index ce8ebc9..391b6bc 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -32,7 +32,8 @@ AC_CONFIG_SRCDIR([src/ls.c])
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_HEADERS([lib/config.h:lib/config.hin])
 
-AM_INIT_AUTOMAKE([1.11.1 no-dist-gzip dist-xz color-tests parallel-tests])
+AM_INIT_AUTOMAKE([1.11.1 no-dist-gzip dist-xz color-tests parallel-tests
+                  subdir-objects])
 AM_SILENT_RULES([yes]) # make --enable-silent-rules the default.
 
 dnl POSIXCHECK is worthwhile for maintainers, but adds several seconds