diff --git a/build-aux/GNUmakefile.in b/build-aux/GNUmakefile.in
index c5ede91e..b7bb7928 100644
--- a/build-aux/GNUmakefile.in
+++ b/build-aux/GNUmakefile.in
@@ -170,10 +170,14 @@ uninstall:
 
 doc/version.texi: ${srcdest}doc/mes.texi GNUmakefile
 	@mkdir -p $(@D)
-	(set `LANG= date -r $< +'%d %B %Y'`;\
-	echo "@set UPDATED $$1 $$2 $$3"; \
-	echo "@set UPDATED-MONTH $$2 $$3"; \
-	echo "@set EDITION $(VERSION)"; \
+	timestamp=$$({ git log --pretty=format:%ct -- $<	\
+		       || date +%s -r $<; }			\
+	               | sort -n -r | head -n 1);		\
+	dmy=$$(date --date="@$$timestamp" "+%-d %B %Y");	\
+	(set `LANG='						\
+	echo "@set UPDATED $$dmy";				\
+	echo "@set UPDATED-MONTH $$my";				\
+	echo "@set EDITION $(VERSION)";				\
 	echo "@set VERSION $(VERSION)") > $@
 
 doc: doc/version.texi