[gtksourceview/wip/modern-autotools] build: update ACLOCAL_AMFLAGS to install third-party macros

[Sébastien Wilmet <swilmet src gnome org>]

commit 57e7b30062bccb76d949186d77b817b8f4db98d5
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sun Aug 9 13:04:58 2015 +0200

    build: update ACLOCAL_AMFLAGS to install third-party macros
    
    So that they are carried around in the distributed tarball, and there
    are no dependencies on things like autoconf-archive.
    
    https://wiki.gnome.org/Projects/GnomeCommon/Migration

 Makefile.am |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index 1ea7474..efaa486 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,4 +1,4 @@
-ACLOCAL_AMFLAGS  = -I m4 ${ACLOCAL_FLAGS}
+ACLOCAL_AMFLAGS = --install -I m4 ${ACLOCAL_FLAGS}
 
 SUBDIRS = gtksourceview po data docs tests