[pygobject] Bring back ChangeLog make target

[Martin Pitt <martinpitt src gnome org>]

commit 299a2fd726f0aceaf67b1cec7a0ef8b21ff7bcbc
Author: Martin Pitt <martinpitt gnome org>
Date:   Mon Jun 25 15:35:19 2012 +0200

    Bring back ChangeLog make target
    
    This is being used by "make dist".

 Makefile.am |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index 6c2f77a..ea537b7 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -98,6 +98,21 @@ release-news:
 
 .PHONY: ChangeLog release-news
 
+ChangeLog:
+	@echo Creating $@
+	@if test -d "$(srcdir)/.git"; then \
+	  (GIT_DIR=$(top_srcdir)/.git ./missing --run git log PYGOBJECT_2_17_0^^.. --stat) | fmt --split-only > $  tmp \
+	  && mv -f $  tmp $@ \
+	  || ($(RM) $  tmp; \
+	      echo Failed to generate ChangeLog, your ChangeLog may be outdated >&2; \
+	      (test -f $@ || echo git-log is required to generate this file >> $@)); \
+	else \
+	  test -f $@ || \
+	  (echo A git checkout and git-log is required to generate ChangeLog >&2 && \
+	  echo A git checkout and git-log is required to generate this file >> $@); \
+	fi
+
+
 distclean-local:
 	if test $(srcdir) = .; then :; else \
 	    rm -f $(BUILT_EXTRA_DIST); \