build: Ensure that makeinfo ≥ 6.8 checks the @menu structure.

See <https://lists.gnu.org/archive/html/bug-texinfo/2023-06/msg00015.html>.

* gettext-tools/doc/Makefile.am (MAKEINFO): Add option
"-c CHECK_NORMAL_MENU_STRUCTURE=1".

diff --git a/gettext-tools/doc/Makefile.am b/gettext-tools/doc/Makefile.am
index cbe144c335c99a73a91ed7dfaee69ed3b5a47e4c..47574e1ecd06b20d6d03b6442ce12a2127251807 100644 (file)
--- a/gettext-tools/doc/Makefile.am
+++ b/gettext-tools/doc/Makefile.am
@@ -1,6 +1,5 @@
 ## Makefile for the gettext-tools/doc subdirectory of GNU gettext
-## Copyright (C) 1995-1997, 2001-2007, 2009, 2013-2015, 2018-2020 Free
-## Software Foundation, Inc.
+## Copyright (C) 1995-2023 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
@@ -33,7 +32,11 @@ TEXINCLUDES = -I $(top_srcdir)/../gettext-runtime/doc
 SED = sed
 RM = rm -f
 
-MAKEINFO = env LANG= LC_MESSAGES= LC_ALL= LANGUAGE= @MAKEINFO@
+# The customization variable CHECK_NORMAL_MENU_STRUCTURE is necessary with
+# makeinfo versions ≥ 6.8.
+MAKEINFO = \
+  env LANG= LC_MESSAGES= LC_ALL= LANGUAGE= \
+  @MAKEINFO@ -c CHECK_NORMAL_MENU_STRUCTURE=1
 MAKEINFOFLAGS = $(TEXINCLUDES) --no-split
 
 info_TEXINFOS = gettext.texi