--- embedaddon/libiconv/srcm4/stddef_h.m4	2012/05/29 09:29:44	1.1
+++ embedaddon/libiconv/srcm4/stddef_h.m4	2021/03/17 13:38:46	1.1.1.2
@@ -1,6 +1,6 @@
-dnl A placeholder for POSIX 2008 <stddef.h>, for platforms that have issues.
-# stddef_h.m4 serial 4
-dnl Copyright (C) 2009-2011 Free Software Foundation, Inc.
+dnl A placeholder for <stddef.h>, for platforms that have issues.
+# stddef_h.m4 serial 6
+dnl Copyright (C) 2009-2019 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.
@@ -10,10 +10,33 @@ AC_DEFUN([gl_STDDEF_H],
   AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
   AC_REQUIRE([gt_TYPE_WCHAR_T])
   STDDEF_H=
+
+  dnl Test whether the type max_align_t exists and whether its alignment
+  dnl "is as great as is supported by the implementation in all contexts".
+  AC_CACHE_CHECK([for good max_align_t],
+    [gl_cv_type_max_align_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <stddef.h>
+            unsigned int s = sizeof (max_align_t);
+            #if defined __GNUC__ || defined __IBM__ALIGNOF__
+            int check1[2 * (__alignof__ (double) <= __alignof__ (max_align_t)) - 1];
+            int check2[2 * (__alignof__ (long double) <= __alignof__ (max_align_t)) - 1];
+            #endif
+          ]])],
+       [gl_cv_type_max_align_t=yes],
+       [gl_cv_type_max_align_t=no])
+    ])
+  if test $gl_cv_type_max_align_t = no; then
+    HAVE_MAX_ALIGN_T=0
+    STDDEF_H=stddef.h
+  fi
+
   if test $gt_cv_c_wchar_t = no; then
     HAVE_WCHAR_T=0
     STDDEF_H=stddef.h
   fi
+
   AC_CACHE_CHECK([whether NULL can be used in arbitrary expressions],
     [gl_cv_decl_null_works],
     [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stddef.h>
@@ -25,6 +48,7 @@ AC_DEFUN([gl_STDDEF_H],
     REPLACE_NULL=1
     STDDEF_H=stddef.h
   fi
+
   AC_SUBST([STDDEF_H])
   AM_CONDITIONAL([GL_GENERATE_STDDEF_H], [test -n "$STDDEF_H"])
   if test -n "$STDDEF_H"; then
@@ -43,5 +67,6 @@ AC_DEFUN([gl_STDDEF_H_DEFAULTS],
 [
   dnl Assume proper GNU behavior unless another module says otherwise.
   REPLACE_NULL=0;                AC_SUBST([REPLACE_NULL])
+  HAVE_MAX_ALIGN_T=1;            AC_SUBST([HAVE_MAX_ALIGN_T])
   HAVE_WCHAR_T=1;                AC_SUBST([HAVE_WCHAR_T])
 ])