[epiphany] Use AX_GENERATE_CHANGELOG

[Michael Catanzaro <mcatanzaro src gnome org>]

commit e25c70a84e7d70d986c33ec4373c0ac73dc2478c
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Sun Aug 7 08:59:43 2016 -0500

    Use AX_GENERATE_CHANGELOG

 Makefile.am  |   14 +++-----------
 configure.ac |    5 +++++
 2 files changed, 8 insertions(+), 11 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index 43e1e1f..4429f21 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -13,17 +13,9 @@ AM_DISTCHECK_CONFIGURE_FLAGS = \
 # Ignore gtk theme cache files on distcheck
 distuninstallcheck_listfiles = find . -type f -print | grep -v 'icon-theme.cache'
 
-# Build ChangeLog from git history
-ChangeLog:
-       @if test -f $(top_srcdir)/.git/HEAD; then \
-               pushd $(top_srcdir); \
-               git log --max-count=500 --no-decorate --stat > $(abs_top_builddir)/$@; \
-               popd; \
-       fi
-
-dist: ChangeLog
-
-.PHONY: ChangeLog
+@GENERATE_CHANGELOG_RULES@
+CHANGELOG_START = $(EPIPHANY_CHANGELOG_START)
+dist-hook: dist-ChangeLog
 
 MAINTAINERCLEANFILES = \
         $(GITIGNORE_MAINTAINERCLEANFILES_TOPLEVEL) \
diff --git a/configure.ac b/configure.ac
index 2b3c2cc..616686e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -19,6 +19,9 @@ m4_define([epiphany_version_minor],[21])
 m4_define([epiphany_version_micro],[4])
 m4_define([epiphany_version],[epiphany_version_major.epiphany_version_minor.epiphany_version_micro])
 
+m4_define([epiphany_previous_version_major],[3])
+m4_define([epiphany_previous_version_minor],[20])
+
 AC_INIT([GNOME Web 
Browser],[epiphany_version],[http://bugzilla.gnome.org/enter_bug.cgi?product=epiphany],[epiphany])
 AX_IS_RELEASE([git-directory])
 
@@ -30,12 +33,14 @@ AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_SRCDIR([configure.ac])
 
 AC_SUBST([EPIPHANY_MAJOR],[epiphany_version_major.epiphany_version_minor])
+AC_SUBST([EPIPHANY_CHANGELOG_START],[epiphany_previous_version_major.epiphany_previous_version_minor.0])
 
 AX_CHECK_ENABLE_DEBUG([yes])
 AX_CODE_COVERAGE
 AX_COMPILER_FLAGS([WARN_CFLAGS], [WARN_LDFLAGS], [$ax_is_release], [],
        dnl TODO: Remove! These warnings should be fixed, not silenced.
        [-Wno-deprecated-declarations])
+AX_GENERATE_CHANGELOG
 
 AC_PROG_CC