[gexiv2] build: Silence automake portability warnings

[Jens Georg <jensgeorg src gnome org>]

commit e97e9ff2c3a490031efaa8bb289ab8f613f91d56
Author: Jens Georg <mail jensge org>
Date:   Sat Apr 30 09:57:05 2016 +0200

    build: Silence automake portability warnings

 configure.ac |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index be23f21..4ef3b6f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5,7 +5,8 @@ AC_CONFIG_MACRO_DIR([m4])
 
 # Will install auxiliary build tools (depcomp, install-sh, missing...) under build-aux/
 AC_CONFIG_AUX_DIR([build-aux])
-AM_INIT_AUTOMAKE([1.11 -Wall no-define foreign dist-xz no-dist-gzip tar-ustar subdir-objects])
+AM_INIT_AUTOMAKE([1.11 -Wall no-define foreign dist-xz no-dist-gzip tar-ustar
+                  subdir-objects -Wno-portability])
 
 AM_MAINTAINER_MODE([enable])
 AM_SILENT_RULES([yes])