[gimp/gimp-2-6] Add Makefile.am rule to generate ChangeLog from git log

[Sven Neumann <neo src gnome org>]

commit d193d08022cbba7fa3bc89af80988eb4fdb72ac2
Author: Martin Nordholts <martinn src gnome org>
Date:   Mon Jul 13 13:23:35 2009 +0200

    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                     |    1 +
 ChangeLog => ChangeLog.pre-git |    1 +
 Makefile.am                    |   21 +++++++++++++++++++++
 3 files changed, 23 insertions(+), 0 deletions(-)
---
diff --git a/.gitignore b/.gitignore
index 5ccb71d..04ca86a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+/ChangeLog
 /Makefile
 /Makefile.in
 /aclocal.m4
diff --git a/ChangeLog b/ChangeLog.pre-git
similarity index 99%
rename from ChangeLog
rename to ChangeLog.pre-git
index 95f4905..b80a409 100644
--- a/ChangeLog
+++ b/ChangeLog.pre-git
@@ -1,3 +1,4 @@
+
 2009-04-03  Michael Natterer  <mitch gimp org>
 
 	Merged from trunk:
diff --git a/Makefile.am b/Makefile.am
index e14583e..1e89a46 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -95,3 +95,24 @@ endif
 all-local: AUTHORS
 
 dist-hook: check-defs validate-authors
+
+
+CHANGELOG_START = f8f3c41320320cb07af2956eca48007a464f14d7
+
+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+	      echo Failed to generate ChangeLog, your ChangeLog may be outdated 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