1 files changed, 40 insertions, 8 deletions

diff --git a/gl/m4/langinfo_h.m4 b/gl/m4/langinfo_h.m4
index 73bef8b..87959f7 100644
--- a/gl/m4/langinfo_h.m4
+++ b/gl/m4/langinfo_h.m4
@@ -1,10 +1,10 @@
-# langinfo_h.m4 serial 7
-dnl Copyright (C) 2009-2013 Free Software Foundation, Inc.
+# langinfo_h.m4 serial 12
+dnl Copyright (C) 2009-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-AC_DEFUN([gl_LANGINFO_H],
+AC_DEFUN_ONCE([gl_LANGINFO_H],
 [
   AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
 
@@ -17,13 +17,17 @@ AC_DEFUN([gl_LANGINFO_H],
   dnl Determine whether <langinfo.h> exists. It is missing on mingw and BeOS.
   HAVE_LANGINFO_CODESET=0
   HAVE_LANGINFO_T_FMT_AMPM=0
+  HAVE_LANGINFO_ALTMON=0
   HAVE_LANGINFO_ERA=0
   HAVE_LANGINFO_YESEXPR=0
   AC_CHECK_HEADERS_ONCE([langinfo.h])
   if test $ac_cv_header_langinfo_h = yes; then
     HAVE_LANGINFO_H=1
-    dnl Determine what <langinfo.h> defines. CODESET and ERA etc. are missing
-    dnl on OpenBSD 3.8. T_FMT_AMPM and YESEXPR, NOEXPR are missing on IRIX 5.3.
+    dnl Determine what <langinfo.h> defines.
+    dnl CODESET is missing on OpenBSD 3.8.
+    dnl ERA etc. are missing on OpenBSD 6.7.
+    dnl T_FMT_AMPM and YESEXPR, NOEXPR are missing on IRIX 5.3.
+    dnl ALTMON_* are missing on glibc 2.26 and many other systems.
     AC_CACHE_CHECK([whether langinfo.h defines CODESET],
       [gl_cv_header_langinfo_codeset],
       [AC_COMPILE_IFELSE(
@@ -48,6 +52,18 @@ int a = T_FMT_AMPM;
     if test $gl_cv_header_langinfo_t_fmt_ampm = yes; then
       HAVE_LANGINFO_T_FMT_AMPM=1
     fi
+    AC_CACHE_CHECK([whether langinfo.h defines ALTMON_1],
+      [gl_cv_header_langinfo_altmon],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = ALTMON_1;
+]])],
+         [gl_cv_header_langinfo_altmon=yes],
+         [gl_cv_header_langinfo_altmon=no])
+      ])
+    if test $gl_cv_header_langinfo_altmon = yes; then
+      HAVE_LANGINFO_ALTMON=1
+    fi
     AC_CACHE_CHECK([whether langinfo.h defines ERA],
       [gl_cv_header_langinfo_era],
       [AC_COMPILE_IFELSE(
@@ -78,6 +94,7 @@ int a = YESEXPR;
   AC_SUBST([HAVE_LANGINFO_H])
   AC_SUBST([HAVE_LANGINFO_CODESET])
   AC_SUBST([HAVE_LANGINFO_T_FMT_AMPM])
+  AC_SUBST([HAVE_LANGINFO_ALTMON])
   AC_SUBST([HAVE_LANGINFO_ERA])
   AC_SUBST([HAVE_LANGINFO_YESEXPR])
 
@@ -87,18 +104,33 @@ int a = YESEXPR;
     ]], [nl_langinfo])
 ])
 
+# gl_LANGINFO_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
 AC_DEFUN([gl_LANGINFO_MODULE_INDICATOR],
 [
-  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
-  AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
+  dnl Ensure to expand the default settings once only.
+  gl_LANGINFO_H_REQUIRE_DEFAULTS
   gl_MODULE_INDICATOR_SET_VARIABLE([$1])
   dnl Define it also as a C macro, for the benefit of the unit tests.
   gl_MODULE_INDICATOR_FOR_TESTS([$1])
 ])
 
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_LANGINFO_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_LANGINFO_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_NL_LANGINFO])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_LANGINFO_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
+])
+
 AC_DEFUN([gl_LANGINFO_H_DEFAULTS],
 [
-  GNULIB_NL_LANGINFO=0;  AC_SUBST([GNULIB_NL_LANGINFO])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_NL_LANGINFO=1;    AC_SUBST([HAVE_NL_LANGINFO])
   REPLACE_NL_LANGINFO=0; AC_SUBST([REPLACE_NL_LANGINFO])