Fix Changelog generation

Makefile.am

@@ -21,18 +21,12 @@ EXTRA_DIST = \
 	autogen.sh \
 	mozo.in
 
+# Build ChangeLog from GIT  history
 ChangeLog:
-	@if test -d "$(srcdir)/.git"; \
-	then \
-		echo Creating ChangeLog && \
-		( cd "$(top_srcdir)" && \
-		  echo '# Generated by Makefile. Do not edit.'; echo; \
-		  $(top_srcdir)/missing --run git log --stat ) > ChangeLog.tmp \
-		&& mv -f ChangeLog.tmp $(distdir)/ChangeLog \
-		|| ( rm -f ChangeLog.tmp ; \
-		     echo Failed to generate ChangeLog >&2 ); \
-	else \
-		echo A git clone is required to generate a ChangeLog >&2; \
+	$(AM_V_GEN) if test -d $(top_srcdir)/.git; then \
+		GIT_DIR="$(top_srcdir)/.git" git log --stat > $@; \
 	fi
 
+dist: ChangeLog
+
 .PHONY: ChangeLog