[PATCH attr] automake: require 1.15+

[Mike Frysinger]

This was released back in 2014, so everyone should have access to it
or newer, and realistically no one is testing automake 2.13 anymore.
---
 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 27c2ef5e604b..8ad7284b47a1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -21,7 +21,7 @@ AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_HEADERS([include/config.h])
 AC_PREFIX_DEFAULT(/usr)
 
-AM_INIT_AUTOMAKE([-Wall foreign 1.13 dist-xz subdir-objects])
+AM_INIT_AUTOMAKE([-Wall foreign 1.15 dist-xz subdir-objects])
 AM_SILENT_RULES([yes])
 
 AC_CANONICAL_HOST
-- 
2.43.0