Index: doc/Makefile.in
--- doc/Makefile.in.orig
+++ doc/Makefile.in
@@ -2452,7 +2452,7 @@ SUFFIXES = .1
 
 # The customization variable CHECK_NORMAL_MENU_STRUCTURE is necessary with
 # makeinfo versions ≥ 6.8.
-AM_MAKEINFOFLAGS = -c CHECK_NORMAL_MENU_STRUCTURE=1
+#AM_MAKEINFOFLAGS = -c CHECK_NORMAL_MENU_STRUCTURE=1
 HELP2MAN = $(SHELL) $(top_srcdir)/build-aux/missing --run help2man
 all: all-am
 
