Automatically generate ChangeLog from git log for release tarball

make dist should use git2cl to generate ChangeLog from git history,
populating the placeholder file in released tarball.

Signed-off-by: Luca Bruno <lucab@debian.org>
Signed-off-by: Spencer Oliver <ntfreak@users.sourceforge.net>

Makefile.am

@@ -68,6 +68,9 @@ TCL_FILES = find $(srcdir)/$(TCL_PATH) -name '*.cfg' -o -name '*.tcl' | \
 		sed -e 's,^$(srcdir)/$(TCL_PATH),,'
 
 dist-hook:
+	if test -d $(srcdir)/.git -a \( ! -e $(distdir)/ChangeLog -o -w $(distdir)/ChangeLog \) ; then \
+		git --git-dir $(srcdir)/.git log | $(srcdir)/tools/git2cl/git2cl > $(distdir)/ChangeLog ; \
+	fi
 	for i in $$($(TCL_FILES)); do \
 		j="$(distdir)/$(TCL_PATH)/$$i" && \
 		mkdir -p "$$(dirname $$j)" && \