>From 6351ed01c42899191155e2b6dd74f077f1cff193 Mon Sep 17 00:00:00 2001
From: Bruno Haible <address@hidden>
Date: Sat, 9 May 2020 02:52:48 +0200
Subject: [PATCH 1/2] mbrtoc32: Avoid compilation failure on Haiku.

* m4/mbrtoc32.m4 (gl_CHECK_FUNC_MBRTOC32): New macro.
(gl_FUNC_MBRTOC32, gl_MBRTOC32_SANITYCHECK): Use it instead of
AC_CHECK_FUNCS_ONCE.
* doc/posix-functions/mbrtoc32.texi: Mention the Haiku problem.
---
 ChangeLog                         |  8 ++++++++
 doc/posix-functions/mbrtoc32.texi |  3 +++
 m4/mbrtoc32.m4                    | 29 ++++++++++++++++++++++++-----
 3 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 0a9cca9..53a672a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
 2020-05-08  Bruno Haible  <address@hidden>
 
+	mbrtoc32: Avoid compilation failure on Haiku.
+	* m4/mbrtoc32.m4 (gl_CHECK_FUNC_MBRTOC32): New macro.
+	(gl_FUNC_MBRTOC32, gl_MBRTOC32_SANITYCHECK): Use it instead of
+	AC_CHECK_FUNCS_ONCE.
+	* doc/posix-functions/mbrtoc32.texi: Mention the Haiku problem.
+
+2020-05-08  Bruno Haible  <address@hidden>
+
 	limits-h: Define LONG_BIT correctly on Haiku/x86_64.
 	* lib/limits.in.h: Define and test _GL_ALREADY_INCLUDING_LIMITS_H.
 
diff --git a/doc/posix-functions/mbrtoc32.texi b/doc/posix-functions/mbrtoc32.texi
index 3151a09..647beb9 100644
--- a/doc/posix-functions/mbrtoc32.texi
+++ b/doc/posix-functions/mbrtoc32.texi
@@ -25,4 +25,7 @@ FreeBSD 12, Solaris 11.4, mingw, MSVC 14.
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+This function is only defined as an inline function on some platforms:
+Haiku 2020.
 @end itemize
diff --git a/m4/mbrtoc32.m4 b/m4/mbrtoc32.m4
index a5dc51a..991bbc8 100644
--- a/m4/mbrtoc32.m4
+++ b/m4/mbrtoc32.m4
@@ -1,4 +1,4 @@
-# mbrtoc32.m4 serial 3
+# mbrtoc32.m4 serial 4
 dnl Copyright (C) 2014-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -13,8 +13,8 @@ AC_DEFUN([gl_FUNC_MBRTOC32],
 
   AC_REQUIRE([gl_MBRTOC32_SANITYCHECK])
 
-  AC_CHECK_FUNCS_ONCE([mbrtoc32])
-  if test $ac_cv_func_mbrtoc32 = no; then
+  AC_REQUIRE([gl_CHECK_FUNC_MBRTOC32])
+  if test $gl_cv_func_mbrtoc32 = no; then
     HAVE_MBRTOC32=0
   else
     if test $REPLACE_MBSTATE_T = 1; then
@@ -43,6 +43,25 @@ AC_DEFUN([gl_FUNC_MBRTOC32],
   fi
 ])
 
+dnl We can't use AC_CHECK_FUNC here, because mbrtoc32() is defined as a
+dnl static inline function on Haiku 2020.
+AC_DEFUN([gl_CHECK_FUNC_MBRTOC32],
+[
+  AC_CACHE_CHECK([for mbrtoc32], [gl_cv_func_mbrtoc32],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <stdlib.h>
+            #include <uchar.h>
+          ]],
+          [[char32_t c;
+            return mbrtoc32 (&c, "", 1, NULL) == 0;
+          ]])
+       ],
+       [gl_cv_func_mbrtoc32=yes],
+       [gl_cv_func_mbrtoc32=no])
+    ])
+])
+
 AC_DEFUN([gl_MBRTOC32_EMPTY_INPUT],
 [
   AC_REQUIRE([AC_PROG_CC])
@@ -122,11 +141,11 @@ dnl Result is HAVE_WORKING_MBRTOC32.
 AC_DEFUN([gl_MBRTOC32_SANITYCHECK],
 [
   AC_REQUIRE([AC_PROG_CC])
-  AC_CHECK_FUNCS_ONCE([mbrtoc32])
+  AC_REQUIRE([gl_CHECK_FUNC_MBRTOC32])
   AC_REQUIRE([gt_LOCALE_FR])
   AC_REQUIRE([gt_LOCALE_ZH_CN])
   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
-  if test $ac_cv_func_mbrtoc32 = no; then
+  if test $gl_cv_func_mbrtoc32 = no; then
     HAVE_WORKING_MBRTOC32=0
   else
     AC_CACHE_CHECK([whether mbrtoc32 works as well as mbrtowc],
-- 
2.7.4