>From bad7a098679f6bfd8573d14e1722765977436643 Mon Sep 17 00:00:00 2001
From: Bruno Haible <bruno@clisp.org>
Date: Sun, 9 May 2021 18:36:41 +0200
Subject: [PATCH 2/2] malloc-gnu, realloc-gnu, calloc-gnu: Ensure errno gets
 set on IRIX.

* m4/malloc.m4 (gl_CHECK_MALLOC_POSIX): Require AC_CANONICAL_HOST. Set
gl_cv_func_malloc_posix to 'no' also on IRIX.
---
 ChangeLog    |  4 ++++
 m4/malloc.m4 | 56 +++++++++++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 49 insertions(+), 11 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index e69f447..b24976a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2021-05-09  Bruno Haible  <bruno@clisp.org>
 
+	malloc-gnu, realloc-gnu, calloc-gnu: Ensure errno gets set on IRIX.
+	* m4/malloc.m4 (gl_CHECK_MALLOC_POSIX): Require AC_CANONICAL_HOST. Set
+	gl_cv_func_malloc_posix to 'no' also on IRIX.
+
 	malloc-gnu, realloc-gnu, calloc-gnu tests: Verify errno is set.
 	* tests/test-malloc-gnu.c: Include <errno.h>.
 	(main): Verify that, when an allocation larger than PTRDIFF_MAX failed,
diff --git a/m4/malloc.m4 b/m4/malloc.m4
index c09006d..de1b2c6 100644
--- a/m4/malloc.m4
+++ b/m4/malloc.m4
@@ -1,4 +1,4 @@
-# malloc.m4 serial 24
+# malloc.m4 serial 25
 dnl Copyright (C) 2007, 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,
@@ -115,20 +115,54 @@ AC_DEFUN([gl_FUNC_MALLOC_POSIX],
 # Set gl_cv_func_malloc_posix to yes or no accordingly.
 AC_DEFUN([gl_CHECK_MALLOC_POSIX],
 [
+  AC_REQUIRE([AC_CANONICAL_HOST])
   AC_CACHE_CHECK([whether malloc, realloc, calloc set errno on failure],
     [gl_cv_func_malloc_posix],
     [
       dnl It is too dangerous to try to allocate a large amount of memory:
       dnl some systems go to their knees when you do that. So assume that
-      dnl all Unix implementations of the function set errno on failure.
-      AC_COMPILE_IFELSE(
-        [AC_LANG_PROGRAM(
-           [[]],
-           [[#if defined _WIN32 && ! defined __CYGWIN__
-             choke me
-             #endif
-            ]])],
-        [gl_cv_func_malloc_posix=yes],
-        [gl_cv_func_malloc_posix=no])
+      dnl all Unix implementations of the function set errno on failure,
+      dnl except on those platforms where we have seen 'test-malloc-gnu',
+      dnl 'test-realloc-gnu', 'test-calloc-gnu' fail.
+      case "$host_os" in
+        mingw*)
+          gl_cv_func_malloc_posix=no ;;
+        irix*)
+          dnl The three functions return NULL with errno unset when the
+          dnl argument is larger than PTRDIFF_MAX. Here is a test program:
+m4_divert_push([KILL])
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#define ptrdiff_t long
+#ifndef PTRDIFF_MAX
+# define PTRDIFF_MAX ((ptrdiff_t) ((1UL << (8 * sizeof (ptrdiff_t) - 1)) - 1))
+#endif
+
+int main ()
+{
+  void *p;
+
+  fprintf (stderr, "PTRDIFF_MAX = %lu\n", (unsigned long) PTRDIFF_MAX);
+
+  errno = 0;
+  p = malloc ((unsigned long) PTRDIFF_MAX + 1);
+  fprintf (stderr, "p=%p errno=%d\n", p, errno);
+
+  errno = 0;
+  p = calloc (PTRDIFF_MAX / 2 + 1, 2);
+  fprintf (stderr, "p=%p errno=%d\n", p, errno);
+
+  errno = 0;
+  p = realloc (NULL, (unsigned long) PTRDIFF_MAX + 1);
+  fprintf (stderr, "p=%p errno=%d\n", p, errno);
+
+  return 0;
+}
+m4_divert_pop([KILL])
+          gl_cv_func_malloc_posix=no ;;
+        *)
+          gl_cv_func_malloc_posix=yes ;;
+      esac
     ])
 ])
-- 
2.7.4