Generate ChangeLog from git log

* .gitignore: Add ChangeLog
* ChangeLog: Rename to ChangeLog-CVS.
* Makefile.am (gen-changelog): New rule.
(dist-hook, .PHONY): Depend on it.
(EXTRA_DIST): Add ChangeLog-CVS.
* README-hacking: New file.
* gitlog-to-changelog: Import from gnulib.
* autogen.sh: Create empty ChangeLog file to make automake strictness
check happy.  Use automated "autoreconf -fiv" instead of manual
invocations of various autotools.

1 files changed, 17 insertions, 0 deletions

diff --git a/README-hacking b/README-hacking
new file mode 100644
index 00000000..d3700943
--- /dev/null
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+No more ChangeLog file
+======================
+Do not create or modify the ChangeLog files.  Starting at 2011-10-26, the
+policy changed.  Before, we would insert the exact same text (or worse,
+sometimes slightly differing) into both the ChangeLog file and the commit
+log.  Now we put that information only in the commit log, and generate
+the ChangeLog file from logs at "make dist" time.  As such, there are
+strict requirements on the form of the commit log messages.
+
+
+Commit log requirements
+=======================
+Each commit log should always start with a one-line summary, the second
+line should be blank, and the remaining lines are usually ChangeLog-style
+entries for all affected files, except the leading TABs which should
+be omitted.  It's OK to write a few lines of prose describing the change,
+when the summary and ChangeLog entries don't give enough of the big picture.