[master] 630817e46 build: Enable automake's subdir-objects option

[Dridi Boukelmoune]

commit 630817e467bf5df8ecd457d35cfd8ad61dfd4560
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Wed Jul 1 14:00:03 2020 +0200

    build: Enable automake's subdir-objects option
    
    We can get rid of autogen.des' egrep command used to silence this
    warning too. In fact we can even remove the subshell and simply
    call autoreconf directly. The problem with egrep is the loss of
    a meaningful exit status for the autoreconf invocation.
    
    I also enabled autoreconf's verbose output.

diff --git a/autogen.des b/autogen.des
index 7ef93d968..44d3f551b 100755
--- a/autogen.des
+++ b/autogen.des
@@ -22,8 +22,8 @@ else
 	DST="--prefix=/opt/varnish --mandir=/opt/varnish/man"
 fi
 
-rm -f configure
-(cd $SRCDIR && autoreconf -i 2>&1 | egrep -v "(subdir-objects|is in a subdirectory)")
+rm -f $SRCDIR/configure
+autoreconf -i -v $SRCDIR
 
 # autoconf prior to 2.62 has issues with zsh 4.2 and newer
 CONFIG_SHELL=/bin/sh
diff --git a/configure.ac b/configure.ac
index cbdeb59cf..f0f5b11db 100644
--- a/configure.ac
+++ b/configure.ac
@@ -19,7 +19,7 @@ AC_CANONICAL_SYSTEM
 AC_LANG(C)
 
 AM_MAINTAINER_MODE([disable])
-AM_INIT_AUTOMAKE([1.11 foreign color-tests parallel-tests])
+AM_INIT_AUTOMAKE([1.11 foreign color-tests parallel-tests subdir-objects])
 AM_SILENT_RULES([yes])
 AC_DISABLE_STATIC
 AC_PROG_LIBTOOL