[gimp-help-2] configure: use tar-pax tar format for make dist.

[Jehan Pagès <jehanp src gnome org>]

commit 889ea05b13a3440e1e9f3b243081857a4a0db702
Author: Jehan <jehan girinstud io>
Date:   Mon Jun 12 02:18:55 2017 +0200

    configure: use tar-pax tar format for make dist.
    
    By default, automake uses tar-v7 which has a limitation of 99 characters
    to paths. This results in many files not being saved inside the tarball,
    while diplaying such error on a `make dist`:
    > tar: gimp-help-2.9.5/some/long/path: file name is too long (max 99); not dumped
    The tar-pax format is newer, without length limitation. See:
    https://www.gnu.org/software/automake/manual/html_node/List-of-Automake-options.html
    It is available since automake 1.9 but it turns out that our minimum
    requirement is already automake 1.10 since commit da28313e but this was
    only visible in the autogen.sh. Let's make the configure script
    consistent as well.

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index d78b368..d4fe01b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -37,7 +37,7 @@ AC_CONFIG_COMMANDS(
 #    cp -f $srcdir/stylesheets/*.xsl $srcdir/stylesheets/*.dtd stylesheets/
 #])
 
-AM_INIT_AUTOMAKE([1.6 dist-bzip2 -Wall -Wno-portability])
+AM_INIT_AUTOMAKE([1.10 tar-pax dist-bzip2 -Wall -Wno-portability])
 
 AM_MAINTAINER_MODE