[libgdata] build: Use AX_IS_RELEASE

[Philip Withnall <pwithnall src gnome org>]

commit 6666a7ac6f24e788bca84ba9d1bda35dfd4d10d1
Author: Philip Withnall <philip withnall collabora co uk>
Date:   Tue May 26 18:43:49 2015 +0100

    build: Use AX_IS_RELEASE
    
    Check for the presence of a git repository to determine whether things
    like compiler warnings should be fatal. The warnings themselves will be
    hooked up later.
    
    This adds an implicit dependency on autoconf-archive or GNOME’s
    m4-common. These are pulled in by JHBuild, and the relevant macros are
    automatically distributed in tarballs — so the dependencies only need to
    be explicitly installed if you are building from git without using
    JHBuild. This is an unsupported use case.
    
    Note that AC_CONFIG_MACRO_DIR() has already been added to configure.ac.
    
    https://wiki.gnome.org/Projects/GnomeCommon/Migration

 configure.ac |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 8a7f355..32a2d78 100644
--- a/configure.ac
+++ b/configure.ac
@@ -11,6 +11,7 @@ m4_define(gdata_api_version_major, 0)
 m4_define(gdata_api_version_minor, 0)
 
 
AC_INIT([libgdata],[gdata_version_major.gdata_version_minor.gdata_version_micro],[https://bugzilla.gnome.org/enter_bug.cgi?product=libgdata],[libgdata],[https://wiki.gnome.org/Projects/libgdata])
+AX_IS_RELEASE([git-directory])
 
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_AUX_DIR([build-aux])