Add Makefile.am rule to generate ChangeLog from git log

Add Makefile.am rule to generate ChangeLog from git log copied from
pango and Behdad Esfahbod.

.gitignore

@@ -7,6 +7,11 @@
 *.patch
 
 
+=======
+*.la
+*.lo
+*.o
+/ChangeLog
 /Makefile
 /Makefile.in
 /aclocal.m4
@@ -24,9 +29,9 @@
 /configure
 /depcomp
 /gimp-2.0.pc
+/gimp-zip
 /gimpthumb-2.0.pc
 /gimpui-2.0.pc
-/gimp-zip
 /gtk-doc.make
 /install-sh
 /intltool-extract
@@ -44,6 +49,3 @@
 /stamp-h
 /stamp-h.in
 /stamp-h1
-*.la
-*.lo
-*.o

ChangeLog.pre-git

@@ -1,36 +1,4 @@
 
-
-
-
-	NOTE: After the migration to git this ChangeLog is no longer used
-	during development. Instead, it will be updated prior to every
-	release based on the git log.
-
-
-
-
-
-2009-04-25  Martin Nordholts  <martinn@svn.gnome.org>
-
-	* app/dialogs/file-save-dialog.c: Introduce
-	file_save_dialog_unkown_ext_msg() so that we don't need to have a
-	copy-pasted huge error message (and prepare for more intricate
-	message handling).
-
-2009-04-24  Martin Nordholts  <martinn@src.gnome.org>
-
-	Convert Subversion references to git
-
-	* HACKING
-	* INSTALL
-	* README.i18n
-	* autogen.sh
-
-2009-04-24  Martin Nordholts  <martinn@src.gnome.org>
-
-	* README: Update link to GTK+ themes in README. Patch from
-	Shlomi Fish.
-
 2009-04-16  Michael Natterer  <mitch@gimp.org>
 
 	* app/paint/gimppaintcore.[ch]: made GimpCoords* parameter of

Makefile.am

@@ -95,3 +95,24 @@ endif
 all-local: AUTHORS
 
 dist-hook: check-defs validate-authors
+
+
+
+CHANGELOG_START = 74424325abb54620b370f2595445b2b2a19fe5e7
+
+ChangeLog: $(srcdir)/ChangeLog $(srcdir)/ChangeLog.pre-git
+$(srcdir)/ChangeLog:
+	@echo Creating $@ based on git log
+	@if test -d "$(srcdir)/.git"; then \
+	  (GIT_DIR=$(top_srcdir)/.git ./missing --run \
+	   git log $(CHANGELOG_START)^.. --stat) | fmt --split-only > $@.tmp \
+	  && mv -f $@.tmp $@ && echo Appending ChangeLog.pre-git && cat ChangeLog.pre-git >> $@ \
+	  || ($(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+	      echo Failed to generate ChangeLog, your ChangeLog may be outdated 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
+.PHONY: $(srcdir)/ChangeLog