Remove support for broken <wchar.h> in BSD/OS and OSF/1.

* lib/wchar.in.h: Don't include <stdio.h>, <time.h>.
* lib/mbchar.h: Likewise.
* lib/mbiter.h: Likewise.
* lib/mbuiter.h: Likewise.
* m4/stdint.m4 (gl_STDINT_INCLUDES): Likewise.
* lib/mbfile.h: Don't include <time.h>.
* lib/mbswidth.h: Update comment.
* lib/stdint.in.h: Don't include <stddef.h>, <stdio.h>, <time.h> before
<wchar.h>.
* lib/wctype.in.h: Likewise.
* m4/btowc.m4 (gl_FUNC_BTOWC): Simplify test programs.
* m4/iswblank.m4 (gl_FUNC_ISWBLANK): Likewise.
* m4/iswdigit.m4 (gl_FUNC_ISWDIGIT): Likewise.
* m4/iswxdigit.m4 (gl_FUNC_ISWXDIGIT): Likewise.
* m4/mbrlen.m4 (gl_FUNC_MBRLEN, gl_MBRLEN_INCOMPLETE_STATE,
gl_MBRLEN_RETVAL, gl_MBRLEN_NUL_RETVAL): Likewise.
* m4/mbrtoc32.m4 (gl_MBRTOC32_SANITYCHECK): Likewise.
* m4/mbrtowc.m4 (gl_FUNC_MBRTOWC, gl_MBRTOWC_INCOMPLETE_STATE,
gl_MBRTOWC_SANITYCHECK, gl_MBRTOWC_NULL_ARG1, gl_MBRTOWC_NULL_ARG2,
gl_MBRTOWC_RETVAL, gl_MBRTOWC_NUL_RETVAL, gl_MBRTOWC_STORES_INCOMPLETE,
AC_FUNC_MBRTOWC): Likewise.
* m4/mbsinit.m4 (gl_FUNC_MBSINIT): Likewise.
* m4/mbsnrtowcs.m4 (gl_MBSNRTOWCS_WORKS_IN_TRADITIONAL_LOCALE):
Likewise.
* m4/mbsrtowcs.m4 (gl_FUNC_MBSRTOWCS, gl_MBSRTOWCS_WORKS): Likewise.
* m4/mbstate_t.m4 (AC_TYPE_MBSTATE_T): Likewise.
* m4/mbswidth.m4 (gl_MBSWIDTH): Likewise.
* m4/printf.m4 (gl_PRINTF_DIRECTIVE_LS): Likewise.
* m4/wchar_h.m4 (gl_WCHAR_H, gl_WCHAR_H_INLINE_OK): Likewise.
* m4/wcrtomb.m4 (gl_FUNC_WCRTOMB): Likewise.
* m4/wcsdup.m4 (gl_FUNC_WCSDUP): Likewise.
* m4/wcsnrtombs.m4 (gl_WCSNRTOMBS_WORKS_IN_TRADITIONAL_LOCALE):
Likewise.
* m4/wcsrtombs.m4 (gl_FUNC_WCSRTOMBS, gl_WCSRTOMBS_TERMINATION,
gl_WCSRTOMBS_NULL): Likewise.
* m4/wcstok.m4 (gl_FUNC_WCSTOK): Likewise.
* m4/wctob.m4 (gl_FUNC_WCTOB): Likewise.
* m4/wctype_h.m4 (gl_WCTYPE_H): Likewise.
* m4/wcwidth.m4 (gl_FUNC_WCWIDTH): Likewise.
* m4/wint_t.m4 (gt_TYPE_WINT_T): Likewise.
* m4/wmemchr.m4 (gl_FUNC_WMEMCHR): Likewise.
* m4/wmemcmp.m4 (gl_FUNC_WMEMCMP): Likewise.
* m4/wmemcpy.m4 (gl_FUNC_WMEMCPY): Likewise.
* m4/wmemmove.m4 (gl_FUNC_WMEMMOVE): Likewise.
* m4/wmemset.m4 (gl_FUNC_WMEMSET): Likewise.

38 files changed, 142 insertions, 565 deletions

diff --git a/ChangeLog b/ChangeLog
index 6dcd2d2a1e..8d070e8b13 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,54 @@
 2020-12-20  Bruno Haible  <bruno@clisp.org>
 
+	Remove support for broken <wchar.h> in BSD/OS and OSF/1.
+	* lib/wchar.in.h: Don't include <stdio.h>, <time.h>.
+	* lib/mbchar.h: Likewise.
+	* lib/mbiter.h: Likewise.
+	* lib/mbuiter.h: Likewise.
+	* m4/stdint.m4 (gl_STDINT_INCLUDES): Likewise.
+	* lib/mbfile.h: Don't include <time.h>.
+	* lib/mbswidth.h: Update comment.
+	* lib/stdint.in.h: Don't include <stddef.h>, <stdio.h>, <time.h> before
+	<wchar.h>.
+	* lib/wctype.in.h: Likewise.
+	* m4/btowc.m4 (gl_FUNC_BTOWC): Simplify test programs.
+	* m4/iswblank.m4 (gl_FUNC_ISWBLANK): Likewise.
+	* m4/iswdigit.m4 (gl_FUNC_ISWDIGIT): Likewise.
+	* m4/iswxdigit.m4 (gl_FUNC_ISWXDIGIT): Likewise.
+	* m4/mbrlen.m4 (gl_FUNC_MBRLEN, gl_MBRLEN_INCOMPLETE_STATE,
+	gl_MBRLEN_RETVAL, gl_MBRLEN_NUL_RETVAL): Likewise.
+	* m4/mbrtoc32.m4 (gl_MBRTOC32_SANITYCHECK): Likewise.
+	* m4/mbrtowc.m4 (gl_FUNC_MBRTOWC, gl_MBRTOWC_INCOMPLETE_STATE,
+	gl_MBRTOWC_SANITYCHECK, gl_MBRTOWC_NULL_ARG1, gl_MBRTOWC_NULL_ARG2,
+	gl_MBRTOWC_RETVAL, gl_MBRTOWC_NUL_RETVAL, gl_MBRTOWC_STORES_INCOMPLETE,
+	AC_FUNC_MBRTOWC): Likewise.
+	* m4/mbsinit.m4 (gl_FUNC_MBSINIT): Likewise.
+	* m4/mbsnrtowcs.m4 (gl_MBSNRTOWCS_WORKS_IN_TRADITIONAL_LOCALE):
+	Likewise.
+	* m4/mbsrtowcs.m4 (gl_FUNC_MBSRTOWCS, gl_MBSRTOWCS_WORKS): Likewise.
+	* m4/mbstate_t.m4 (AC_TYPE_MBSTATE_T): Likewise.
+	* m4/mbswidth.m4 (gl_MBSWIDTH): Likewise.
+	* m4/printf.m4 (gl_PRINTF_DIRECTIVE_LS): Likewise.
+	* m4/wchar_h.m4 (gl_WCHAR_H, gl_WCHAR_H_INLINE_OK): Likewise.
+	* m4/wcrtomb.m4 (gl_FUNC_WCRTOMB): Likewise.
+	* m4/wcsdup.m4 (gl_FUNC_WCSDUP): Likewise.
+	* m4/wcsnrtombs.m4 (gl_WCSNRTOMBS_WORKS_IN_TRADITIONAL_LOCALE):
+	Likewise.
+	* m4/wcsrtombs.m4 (gl_FUNC_WCSRTOMBS, gl_WCSRTOMBS_TERMINATION,
+	gl_WCSRTOMBS_NULL): Likewise.
+	* m4/wcstok.m4 (gl_FUNC_WCSTOK): Likewise.
+	* m4/wctob.m4 (gl_FUNC_WCTOB): Likewise.
+	* m4/wctype_h.m4 (gl_WCTYPE_H): Likewise.
+	* m4/wcwidth.m4 (gl_FUNC_WCWIDTH): Likewise.
+	* m4/wint_t.m4 (gt_TYPE_WINT_T): Likewise.
+	* m4/wmemchr.m4 (gl_FUNC_WMEMCHR): Likewise.
+	* m4/wmemcmp.m4 (gl_FUNC_WMEMCMP): Likewise.
+	* m4/wmemcpy.m4 (gl_FUNC_WMEMCPY): Likewise.
+	* m4/wmemmove.m4 (gl_FUNC_WMEMMOVE): Likewise.
+	* m4/wmemset.m4 (gl_FUNC_WMEMSET): Likewise.
+
+2020-12-20  Bruno Haible  <bruno@clisp.org>
+
 	isnanf: Fix autoconf test.
 	* m4/isnanf.m4 (gl_ISNANF_WORKS): Fix one of the NaN tests.
 
diff --git a/lib/mbchar.h b/lib/mbchar.h
index 8ff58bf519..111a6fbefd 100644
--- a/lib/mbchar.h
+++ b/lib/mbchar.h
@@ -146,13 +146,6 @@
 
 #include <stdbool.h>
 #include <string.h>
-
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.1 has a bug: <stdio.h> and <time.h> must be included before
-   <wchar.h>.  */
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 #include <wctype.h>
 
diff --git a/lib/mbfile.h b/lib/mbfile.h
index 6c86116f1c..d66a443076 100644
--- a/lib/mbfile.h
+++ b/lib/mbfile.h
@@ -51,13 +51,6 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include <string.h>
-
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.1 has a bug: <stdio.h> and <time.h> must be included before
-   <wchar.h>.  */
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 
 #include "mbchar.h"
diff --git a/lib/mbiter.h b/lib/mbiter.h
index a8c4d4e7ba..a26be1ad32 100644
--- a/lib/mbiter.h
+++ b/lib/mbiter.h
@@ -86,13 +86,6 @@
 #include <stdbool.h>
 #include <stddef.h>
 #include <string.h>
-
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.1 has a bug: <stdio.h> and <time.h> must be included before
-   <wchar.h>.  */
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 
 #include "mbchar.h"
diff --git a/lib/mbswidth.h b/lib/mbswidth.h
index 50ef747da8..9f7b033a0f 100644
--- a/lib/mbswidth.h
+++ b/lib/mbswidth.h
@@ -18,12 +18,7 @@
 
 /* Avoid a clash of our mbswidth() with a function of the same name defined
    in UnixWare 7.1.1 <wchar.h>.  We need this #include before the #define
-   below.
-   However, we don't want to #include <wchar.h> on all platforms because
-   - Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-     <wchar.h>.
-   - BSD/OS 4.1 has a bug: <stdio.h> and <time.h> must be included before
-     <wchar.h>.  */
+   below.  */
 #if HAVE_DECL_MBSWIDTH_IN_WCHAR_H
 # include <wchar.h>
 #endif
diff --git a/lib/mbuiter.h b/lib/mbuiter.h
index 2d2a11b997..1848febb63 100644
--- a/lib/mbuiter.h
+++ b/lib/mbuiter.h
@@ -94,13 +94,6 @@
 #include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
-
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.1 has a bug: <stdio.h> and <time.h> must be included before
-   <wchar.h>.  */
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 
 #include "mbchar.h"
diff --git a/lib/stdint.in.h b/lib/stdint.in.h
index cbfb53b438..74ca4cf301 100644
--- a/lib/stdint.in.h
+++ b/lib/stdint.in.h
@@ -579,11 +579,6 @@ typedef int _verify_intmax_size[sizeof (intmax_t) == sizeof (uintmax_t)
    <wchar.h> -> <stdio.h> -> <getopt.h> -> <stdlib.h>, and the latter includes
    <stdint.h> and assumes its types are already defined.  */
 # if @HAVE_WCHAR_H@ && ! (defined WCHAR_MIN && defined WCHAR_MAX)
-  /* BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-     included before <wchar.h>.  */
-#  include <stddef.h>
-#  include <stdio.h>
-#  include <time.h>
 #  define _GL_JUST_INCLUDE_SYSTEM_WCHAR_H
 #  include <wchar.h>
 #  undef _GL_JUST_INCLUDE_SYSTEM_WCHAR_H
diff --git a/lib/wchar.in.h b/lib/wchar.in.h
index 9bc31b230e..8932a4707a 100644
--- a/lib/wchar.in.h
+++ b/lib/wchar.in.h
@@ -65,20 +65,12 @@
 # include <features.h> /* for __GLIBC__ */
 #endif
 
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.
-   In some builds of uClibc, <wchar.h> is nonexistent and wchar_t is defined
+/* In some builds of uClibc, <wchar.h> is nonexistent and wchar_t is defined
    by <stddef.h>.
    But avoid namespace pollution on glibc systems.  */
 #if !(defined __GLIBC__ && !defined __UCLIBC__)
 # include <stddef.h>
 #endif
-#ifndef __GLIBC__
-# include <stdio.h>
-# include <time.h>
-#endif
 
 /* Include the original <wchar.h> if it exists.
    Some builds of uClibc lack it.  */
diff --git a/lib/wctype.in.h b/lib/wctype.in.h
index 06f3e073ab..67e38b325e 100644
--- a/lib/wctype.in.h
+++ b/lib/wctype.in.h
@@ -45,14 +45,7 @@
 #ifndef _@GUARD_PREFIX@_WCTYPE_H
 
 #if @HAVE_WINT_T@
-/* Solaris 2.5 has a bug: <wchar.h> must be included before <wctype.h>.
-   Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-# include <stddef.h>
-# include <stdio.h>
-# include <time.h>
+/* Solaris 2.5 has a bug: <wchar.h> must be included before <wctype.h>.  */
 # include <wchar.h>
 #endif
 
diff --git a/m4/btowc.m4 b/m4/btowc.m4
index c28ccb2416..ec19ea01fc 100644
--- a/m4/btowc.m4
+++ b/m4/btowc.m4
@@ -1,4 +1,4 @@
-# btowc.m4 serial 11
+# btowc.m4 serial 12
 dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -28,14 +28,6 @@ AC_DEFUN([gl_FUNC_BTOWC],
       [
         AC_RUN_IFELSE(
           [AC_LANG_SOURCE([[
-#include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -79,14 +71,7 @@ changequote([,])dnl
           AC_RUN_IFELSE(
             [AC_LANG_SOURCE([[
 #include <locale.h>
-#include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
 #include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
diff --git a/m4/iswblank.m4 b/m4/iswblank.m4
index 387e98dc08..dd6ed94d4d 100644
--- a/m4/iswblank.m4
+++ b/m4/iswblank.m4
@@ -1,4 +1,4 @@
-# iswblank.m4 serial 4
+# iswblank.m4 serial 5
 dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -12,16 +12,9 @@ AC_DEFUN([gl_FUNC_ISWBLANK],
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   AC_CHECK_FUNCS_ONCE([iswblank])
   AC_CHECK_DECLS([iswblank], , , [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
-   before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-#include <wctype.h>
-]])
+    #include <wchar.h>
+    #include <wctype.h>
+  ]])
   if test $ac_cv_func_iswblank = no; then
     HAVE_ISWBLANK=0
     if test $ac_cv_have_decl_iswblank = yes; then
diff --git a/m4/iswdigit.m4 b/m4/iswdigit.m4
index 5f15c39fb9..4ad6a42fdf 100644
--- a/m4/iswdigit.m4
+++ b/m4/iswdigit.m4
@@ -1,4 +1,4 @@
-# iswdigit.m4 serial 1
+# iswdigit.m4 serial 2
 dnl Copyright (C) 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,
@@ -37,13 +37,6 @@ changequote([,])dnl
 #include <locale.h>
 #include <stdlib.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 #include <wctype.h>
 
diff --git a/m4/iswxdigit.m4 b/m4/iswxdigit.m4
index 82190137f1..c63e81e116 100644
--- a/m4/iswxdigit.m4
+++ b/m4/iswxdigit.m4
@@ -1,4 +1,4 @@
-# iswxdigit.m4 serial 1
+# iswxdigit.m4 serial 2
 dnl Copyright (C) 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,
@@ -36,13 +36,6 @@ changequote([,])dnl
 #include <locale.h>
 #include <stdlib.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 #include <wctype.h>
 
diff --git a/m4/mbrlen.m4 b/m4/mbrlen.m4
index 215f9ff369..a42d1d7149 100644
--- a/m4/mbrlen.m4
+++ b/m4/mbrlen.m4
@@ -1,4 +1,4 @@
-# mbrlen.m4 serial 10  -*- coding: utf-8 -*-
+# mbrlen.m4 serial 11  -*- coding: utf-8 -*-
 dnl Copyright (C) 2008, 2010-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -14,15 +14,8 @@ AC_DEFUN([gl_FUNC_MBRLEN],
   if test $ac_cv_func_mbrlen = no; then
     HAVE_MBRLEN=0
     AC_CHECK_DECLS([mbrlen],,, [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]])
+      #include <wchar.h>
+    ]])
     if test $ac_cv_have_decl_mbrlen = yes; then
       dnl On Minix 3.1.8, the system's <wchar.h> declares mbrlen() although
       dnl it does not have the function. Avoid a collision with gnulib's
@@ -67,13 +60,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -125,13 +111,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -199,13 +178,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
diff --git a/m4/mbrtoc32.m4 b/m4/mbrtoc32.m4
index 5b5e9380e5..be6176b53c 100644
--- a/m4/mbrtoc32.m4
+++ b/m4/mbrtoc32.m4
@@ -1,4 +1,4 @@
-# mbrtoc32.m4 serial 5
+# mbrtoc32.m4 serial 6
 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,
@@ -173,13 +173,6 @@ changequote([,])dnl
 #include <locale.h>
 #include <stdlib.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 #include <uchar.h>
 int main ()
diff --git a/m4/mbrtowc.m4 b/m4/mbrtowc.m4
index 755f8c9050..ad31a7b779 100644
--- a/m4/mbrtowc.m4
+++ b/m4/mbrtowc.m4
@@ -1,4 +1,4 @@
-# mbrtowc.m4 serial 37  -*- coding: utf-8 -*-
+# mbrtowc.m4 serial 38  -*- coding: utf-8 -*-
 dnl Copyright (C) 2001-2002, 2004-2005, 2008-2020 Free Software Foundation,
 dnl Inc.
 dnl This file is free software; the Free Software Foundation
@@ -18,15 +18,8 @@ AC_DEFUN([gl_FUNC_MBRTOWC],
   if test $ac_cv_func_mbrtowc = no; then
     HAVE_MBRTOWC=0
     AC_CHECK_DECLS([mbrtowc],,, [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]])
+      #include <wchar.h>
+    ]])
     if test $ac_cv_have_decl_mbrtowc = yes; then
       dnl On Minix 3.1.8, the system's <wchar.h> declares mbrtowc() although
       dnl it does not have the function. Avoid a collision with gnulib's
@@ -181,13 +174,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -213,13 +199,6 @@ int main ()
             [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -271,13 +250,6 @@ changequote([,])dnl
 #include <locale.h>
 #include <stdlib.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -331,13 +303,6 @@ changequote([,])dnl
 #include <locale.h>
 #include <stdlib.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -400,13 +365,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -462,13 +420,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -590,13 +541,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -644,13 +588,6 @@ changequote([,])dnl
            [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -708,13 +645,6 @@ int main ()
              [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -845,14 +775,7 @@ AC_DEFUN([AC_FUNC_MBRTOWC],
     [gl_cv_func_mbrtowc],
     [AC_LINK_IFELSE(
        [AC_LANG_PROGRAM(
-            [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
-                 included before <wchar.h>.
-                 BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
-                 must be included before <wchar.h>.  */
-              #include <stddef.h>
-              #include <stdio.h>
-              #include <time.h>
-              #include <wchar.h>]],
+            [[#include <wchar.h>]],
             [[wchar_t wc;
               char const s[] = "";
               size_t n = 1;
diff --git a/m4/mbsinit.m4 b/m4/mbsinit.m4
index 8c26b6b971..f446659430 100644
--- a/m4/mbsinit.m4
+++ b/m4/mbsinit.m4
@@ -1,4 +1,4 @@
-# mbsinit.m4 serial 8
+# mbsinit.m4 serial 9
 dnl Copyright (C) 2008, 2010-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -16,15 +16,8 @@ AC_DEFUN([gl_FUNC_MBSINIT],
   if test $ac_cv_func_mbsinit = no; then
     HAVE_MBSINIT=0
     AC_CHECK_DECLS([mbsinit],,, [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]])
+      #include <wchar.h>
+    ]])
     if test $ac_cv_have_decl_mbsinit = yes; then
       dnl On Minix 3.1.8, the system's <wchar.h> declares mbsinit() although
       dnl it does not have the function. Avoid a collision with gnulib's
diff --git a/m4/mbsnrtowcs.m4 b/m4/mbsnrtowcs.m4
index 8021043fbe..d023158221 100644
--- a/m4/mbsnrtowcs.m4
+++ b/m4/mbsnrtowcs.m4
@@ -1,4 +1,4 @@
-# mbsnrtowcs.m4 serial 5
+# mbsnrtowcs.m4 serial 6
 dnl Copyright (C) 2008, 2010-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -62,13 +62,6 @@ changequote([,])dnl
 #include <locale.h>
 #include <stdlib.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
diff --git a/m4/mbsrtowcs.m4 b/m4/mbsrtowcs.m4
index e0bc229de5..5a558c3ddb 100644
--- a/m4/mbsrtowcs.m4
+++ b/m4/mbsrtowcs.m4
@@ -1,4 +1,4 @@
-# mbsrtowcs.m4 serial 13
+# mbsrtowcs.m4 serial 14
 dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -15,15 +15,8 @@ AC_DEFUN([gl_FUNC_MBSRTOWCS],
   if test $ac_cv_func_mbsrtowcs = no; then
     HAVE_MBSRTOWCS=0
     AC_CHECK_DECLS([mbsrtowcs],,, [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]])
+      #include <wchar.h>
+    ]])
     if test $ac_cv_have_decl_mbsrtowcs = yes; then
       dnl On Minix 3.1.8, the system's <wchar.h> declares mbsrtowcs() although
       dnl it does not have the function. Avoid a collision with gnulib's
@@ -72,13 +65,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
diff --git a/m4/mbstate_t.m4 b/m4/mbstate_t.m4
index 057ce12ebe..226f1228dd 100644
--- a/m4/mbstate_t.m4
+++ b/m4/mbstate_t.m4
@@ -1,4 +1,4 @@
-# mbstate_t.m4 serial 13
+# mbstate_t.m4 serial 14
 dnl Copyright (C) 2000-2002, 2008-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -20,14 +20,7 @@ AC_DEFUN([AC_TYPE_MBSTATE_T],
      [AC_COMPILE_IFELSE(
         [AC_LANG_PROGRAM(
            [AC_INCLUDES_DEFAULT[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>]],
+             #include <wchar.h>]],
            [[mbstate_t x; return sizeof x;]])],
         [ac_cv_type_mbstate_t=yes],
         [ac_cv_type_mbstate_t=no])])
diff --git a/m4/mbswidth.m4 b/m4/mbswidth.m4
index 45b4f0dac8..c5278dd81e 100644
--- a/m4/mbswidth.m4
+++ b/m4/mbswidth.m4
@@ -1,4 +1,4 @@
-# mbswidth.m4 serial 18
+# mbswidth.m4 serial 19
 dnl Copyright (C) 2000-2002, 2004, 2006-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -18,19 +18,10 @@ AC_DEFUN([gl_MBSWIDTH],
     [ac_cv_have_decl_mbswidth],
     [AC_COMPILE_IFELSE(
        [AC_LANG_PROGRAM(
-          [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
-   before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
+          [[#include <wchar.h>
           ]],
-          [[
-  char *p = (char *) mbswidth;
-  return !p;
+          [[char *p = (char *) mbswidth;
+            return !p;
           ]])],
        [ac_cv_have_decl_mbswidth=yes],
        [ac_cv_have_decl_mbswidth=no])])
diff --git a/m4/printf.m4 b/m4/printf.m4
index eeb792b1e4..95f7d9f130 100644
--- a/m4/printf.m4
+++ b/m4/printf.m4
@@ -1,4 +1,4 @@
-# printf.m4 serial 70
+# printf.m4 serial 71
 dnl Copyright (C) 2003, 2007-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -759,13 +759,7 @@ AC_DEFUN([gl_PRINTF_DIRECTIVE_LS],
     [
       AC_RUN_IFELSE(
         [AC_LANG_SOURCE([[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
 #include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 #include <string.h>
 int main ()
diff --git a/m4/stdint.m4 b/m4/stdint.m4
index 95c0944dc6..adaea3e582 100644
--- a/m4/stdint.m4
+++ b/m4/stdint.m4
@@ -1,4 +1,4 @@
-# stdint.m4 serial 57
+# stdint.m4 serial 58
 dnl Copyright (C) 2001-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -493,13 +493,9 @@ AC_DEFUN([gl_INTEGER_TYPE_SUFFIX],
 dnl gl_STDINT_INCLUDES
 AC_DEFUN([gl_STDINT_INCLUDES],
 [[
-  /* BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-     included before <wchar.h>.  */
   #include <stddef.h>
   #include <signal.h>
   #if HAVE_WCHAR_H
-  # include <stdio.h>
-  # include <time.h>
   # include <wchar.h>
   #endif
 ]])
diff --git a/m4/wchar_h.m4 b/m4/wchar_h.m4
index e0a4060018..f534cf7584 100644
--- a/m4/wchar_h.m4
+++ b/m4/wchar_h.m4
@@ -7,7 +7,7 @@ dnl with or without modifications, as long as this notice is preserved.
 
 dnl Written by Eric Blake.
 
-# wchar_h.m4 serial 48
+# wchar_h.m4 serial 49
 
 AC_DEFUN([gl_WCHAR_H],
 [
@@ -40,16 +40,7 @@ AC_DEFUN([gl_WCHAR_H],
   dnl Check for declarations of anything we want to poison if the
   dnl corresponding gnulib module is not in use.
   gl_WARN_ON_USE_PREPARE([[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#if !(defined __GLIBC__ && !defined __UCLIBC__)
-# include <stddef.h>
-# include <stdio.h>
-# include <time.h>
-#endif
-#include <wchar.h>
+      #include <wchar.h>
     ]],
     [btowc wctob mbsinit mbrtowc mbrlen mbsrtowcs mbsnrtowcs wcrtomb
      wcsrtombs wcsnrtombs wcwidth
@@ -62,16 +53,7 @@ AC_DEFUN([gl_WCHAR_H],
   AC_REQUIRE([AC_C_RESTRICT])
 
   AC_CHECK_DECLS([wcsdup], [], [], [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#if !(defined __GLIBC__ && !defined __UCLIBC__)
-# include <stddef.h>
-# include <stdio.h>
-# include <time.h>
-#endif
-#include <wchar.h>
+      #include <wchar.h>
     ]])
   if test $ac_cv_have_decl_wcsdup = no; then
     HAVE_DECL_WCSDUP=0
@@ -93,18 +75,12 @@ AC_DEFUN([gl_WCHAR_H_INLINE_OK],
      case "$host_os" in
        *-gnu* | gnu*)
          AC_LANG_CONFTEST([
-           AC_LANG_SOURCE([[#define wcstod renamed_wcstod
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-extern int zero (void);
-int main () { return zero(); }
-]])])
+           AC_LANG_SOURCE([[
+             #define wcstod renamed_wcstod
+             #include <wchar.h>
+             extern int zero (void);
+             int main () { return zero(); }
+           ]])])
          dnl Do not rename the object file from conftest.$ac_objext to
          dnl conftest1.$ac_objext, as this will cause the link to fail on
          dnl z/OS when using the XPLINK object format (due to duplicate
@@ -115,17 +91,11 @@ int main () { return zero(); }
          if echo '#include "conftest.c"' >conftest1.c \
             && AC_TRY_EVAL([ac_compile]); then
            AC_LANG_CONFTEST([
-             AC_LANG_SOURCE([[#define wcstod renamed_wcstod
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-int zero (void) { return 0; }
-]])])
+             AC_LANG_SOURCE([[
+               #define wcstod renamed_wcstod
+               #include <wchar.h>
+               int zero (void) { return 0; }
+             ]])])
            dnl See note above about renaming object files.
            ac_compile=`echo "$save_ac_compile" | sed s/conftest/conftest2/`
            if echo '#include "conftest.c"' >conftest2.c \
diff --git a/m4/wcrtomb.m4 b/m4/wcrtomb.m4
index c45fd9830f..71c48f1efb 100644
--- a/m4/wcrtomb.m4
+++ b/m4/wcrtomb.m4
@@ -1,4 +1,4 @@
-# wcrtomb.m4 serial 16
+# wcrtomb.m4 serial 17
 dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -15,15 +15,8 @@ AC_DEFUN([gl_FUNC_WCRTOMB],
   if test $ac_cv_func_wcrtomb = no; then
     HAVE_WCRTOMB=0
     AC_CHECK_DECLS([wcrtomb],,, [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]])
+      #include <wchar.h>
+    ]])
     if test $ac_cv_have_decl_wcrtomb = yes; then
       dnl On Minix 3.1.8, the system's <wchar.h> declares wcrtomb() although
       dnl it does not have the function. Avoid a collision with gnulib's
@@ -52,12 +45,6 @@ AC_DEFUN([gl_FUNC_WCRTOMB],
            [AC_LANG_SOURCE([[
 #include <string.h>
 #include <stdlib.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
 #include <wchar.h>
 int main ()
 {
@@ -105,13 +92,6 @@ changequote([,])dnl
               [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 #include <stdlib.h>
 int main ()
diff --git a/m4/wcsdup.m4 b/m4/wcsdup.m4
index d0dde1cdef..3f63850d0e 100644
--- a/m4/wcsdup.m4
+++ b/m4/wcsdup.m4
@@ -1,4 +1,4 @@
-# wcsdup.m4 serial 3
+# wcsdup.m4 serial 4
 dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,15 +11,7 @@ AC_DEFUN([gl_FUNC_WCSDUP],
     [gl_cv_func_wcsdup],
     [AC_LINK_IFELSE(
        [AC_LANG_PROGRAM(
-          [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
-   before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
+          [[#include <wchar.h>
           ]GL_MDA_DEFINES],
           [[return wcsdup (L"hello") != NULL;]])
        ],
diff --git a/m4/wcsnrtombs.m4 b/m4/wcsnrtombs.m4
index 1acb153c8b..21707b0d73 100644
--- a/m4/wcsnrtombs.m4
+++ b/m4/wcsnrtombs.m4
@@ -1,4 +1,4 @@
-# wcsnrtombs.m4 serial 6
+# wcsnrtombs.m4 serial 7
 dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -60,13 +60,6 @@ changequote([,])dnl
 #include <locale.h>
 #include <stdlib.h>
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
diff --git a/m4/wcsrtombs.m4 b/m4/wcsrtombs.m4
index b94e54ebca..443711c1f6 100644
--- a/m4/wcsrtombs.m4
+++ b/m4/wcsrtombs.m4
@@ -1,4 +1,4 @@
-# wcsrtombs.m4 serial 12
+# wcsrtombs.m4 serial 13
 dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -15,15 +15,8 @@ AC_DEFUN([gl_FUNC_WCSRTOMBS],
   if test $ac_cv_func_wcsrtombs = no; then
     HAVE_WCSRTOMBS=0
     AC_CHECK_DECLS([wcsrtombs],,, [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]])
+      #include <wchar.h>
+    ]])
     if test $ac_cv_have_decl_wcsrtombs = yes; then
       dnl On Minix 3.1.8, the system's <wchar.h> declares wcsrtombs() although
       dnl it does not have the function. Avoid a collision with gnulib's
@@ -84,13 +77,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <stdlib.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -148,13 +134,6 @@ changequote([,])dnl
           [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <stdlib.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
diff --git a/m4/wcstok.m4 b/m4/wcstok.m4
index d61d387397..4f73292ff1 100644
--- a/m4/wcstok.m4
+++ b/m4/wcstok.m4
@@ -1,4 +1,4 @@
-# wcstok.m4 serial 5
+# wcstok.m4 serial 6
 dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -25,17 +25,9 @@ AC_DEFUN([gl_FUNC_WCSTOK],
           [gl_cv_func_wcstok_posix_signature],
           [AC_COMPILE_IFELSE(
              [AC_LANG_PROGRAM(
-                [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-wchar_t *wcstok (wchar_t *, const wchar_t *, wchar_t **);
-]],
+                [[#include <wchar.h>
+                  wchar_t *wcstok (wchar_t *, const wchar_t *, wchar_t **);
+                ]],
                 [[]])],
              [gl_cv_func_wcstok_posix_signature=yes],
              [gl_cv_func_wcstok_posix_signature=no])
diff --git a/m4/wctob.m4 b/m4/wctob.m4
index 801332620b..553c25b9a2 100644
--- a/m4/wctob.m4
+++ b/m4/wctob.m4
@@ -1,4 +1,4 @@
-# wctob.m4 serial 12
+# wctob.m4 serial 13
 dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -43,13 +43,6 @@ changequote([,])dnl
             AC_RUN_IFELSE(
               [AC_LANG_SOURCE([[
 #include <locale.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 
 register long global __asm__ ("%ebx");
@@ -75,14 +68,6 @@ int main ()
             [AC_LANG_SOURCE([[
 #include <locale.h>
 #include <stdlib.h>
-#include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 int main ()
 {
@@ -109,15 +94,8 @@ int main ()
 
       dnl IRIX 6.5 has the wctob() function but does not declare it.
       AC_CHECK_DECLS([wctob], [], [], [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
-   before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]])
+        #include <wchar.h>
+      ]])
       if test $ac_cv_have_decl_wctob != yes; then
         HAVE_DECL_WCTOB=0
       fi
diff --git a/m4/wctype_h.m4 b/m4/wctype_h.m4
index a3cfc833fd..5f189780e3 100644
--- a/m4/wctype_h.m4
+++ b/m4/wctype_h.m4
@@ -1,4 +1,4 @@
-# wctype_h.m4 serial 25
+# wctype_h.m4 serial 26
 
 dnl A placeholder for ISO C99 <wctype.h>, for platforms that lack it.
 
@@ -41,13 +41,6 @@ AC_DEFUN([gl_WCTYPE_H],
         [
           AC_RUN_IFELSE(
             [AC_LANG_SOURCE([[
-               /* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
-                  included before <wchar.h>.
-                  BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
-                  must be included before <wchar.h>.  */
-               #include <stddef.h>
-               #include <stdio.h>
-               #include <time.h>
                #include <wchar.h>
                #include <wctype.h>
                int main () { return iswprint ('x') == 0; }
@@ -92,14 +85,7 @@ AC_DEFUN([gl_WCTYPE_H],
       REPLACE_TOWLOWER=0
     else
       AC_CHECK_DECLS([towlower],,,
-        [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
-             included before <wchar.h>.
-             BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
-             must be included before <wchar.h>.  */
-          #include <stddef.h>
-          #include <stdio.h>
-          #include <time.h>
-          #include <wchar.h>
+        [[#include <wchar.h>
           #if HAVE_WCTYPE_H
           # include <wctype.h>
           #endif
@@ -128,14 +114,7 @@ AC_DEFUN([gl_WCTYPE_H],
   AC_CACHE_CHECK([for wctype_t], [gl_cv_type_wctype_t],
     [AC_COMPILE_IFELSE(
        [AC_LANG_PROGRAM(
-          [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
-               included before <wchar.h>.
-               BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
-               must be included before <wchar.h>.  */
-            #include <stddef.h>
-            #include <stdio.h>
-            #include <time.h>
-            #include <wchar.h>
+          [[#include <wchar.h>
             #if HAVE_WCTYPE_H
             # include <wctype.h>
             #endif
@@ -154,14 +133,7 @@ AC_DEFUN([gl_WCTYPE_H],
   AC_CACHE_CHECK([for wctrans_t], [gl_cv_type_wctrans_t],
     [AC_COMPILE_IFELSE(
        [AC_LANG_PROGRAM(
-          [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
-               included before <wchar.h>.
-               BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
-               must be included before <wchar.h>.  */
-            #include <stddef.h>
-            #include <stdio.h>
-            #include <time.h>
-            #include <wchar.h>
+          [[#include <wchar.h>
             #include <wctype.h>
             wctrans_t a;
           ]],
@@ -176,14 +148,7 @@ AC_DEFUN([gl_WCTYPE_H],
   dnl Check for declarations of anything we want to poison if the
   dnl corresponding gnulib module is not in use.
   gl_WARN_ON_USE_PREPARE([[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
 #if !(defined __GLIBC__ && !defined __UCLIBC__)
-# include <stddef.h>
-# include <stdio.h>
-# include <time.h>
 # include <wchar.h>
 #endif
 #include <wctype.h>
diff --git a/m4/wcwidth.m4 b/m4/wcwidth.m4
index 8b59b4b528..2db36d2750 100644
--- a/m4/wcwidth.m4
+++ b/m4/wcwidth.m4
@@ -1,4 +1,4 @@
-# wcwidth.m4 serial 31
+# wcwidth.m4 serial 32
 dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -21,13 +21,6 @@ AC_DEFUN([gl_FUNC_WCWIDTH],
   AC_CHECK_DECLS([wcwidth], [], [], [[
 /* AIX 3.2.5 declares wcwidth in <string.h>. */
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
-   before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 ]])
   if test $ac_cv_have_decl_wcwidth != yes; then
@@ -64,13 +57,6 @@ AC_DEFUN([gl_FUNC_WCWIDTH],
 #include <locale.h>
 /* AIX 3.2.5 declares wcwidth in <string.h>. */
 #include <string.h>
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
-   before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
 #include <wchar.h>
 #if !HAVE_DECL_WCWIDTH
 extern
diff --git a/m4/wint_t.m4 b/m4/wint_t.m4
index cf9764da3c..16618e8129 100644
--- a/m4/wint_t.m4
+++ b/m4/wint_t.m4
@@ -1,4 +1,4 @@
-# wint_t.m4 serial 9
+# wint_t.m4 serial 10
 dnl Copyright (C) 2003, 2007-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -14,15 +14,7 @@ AC_DEFUN([gt_TYPE_WINT_T],
   AC_CACHE_CHECK([for wint_t], [gt_cv_c_wint_t],
     [AC_COMPILE_IFELSE(
        [AC_LANG_PROGRAM(
-          [[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
-   before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
+          [[#include <wchar.h>
             wint_t foo = (wchar_t)'\0';]],
           [[]])],
        [gt_cv_c_wint_t=yes],
@@ -35,18 +27,9 @@ AC_DEFUN([gt_TYPE_WINT_T],
     AC_CACHE_CHECK([whether wint_t is large enough],
       [gl_cv_type_wint_t_large_enough],
       [AC_COMPILE_IFELSE(
-         [AC_LANG_PROGRAM([[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
-   included before <wchar.h>.  */
-#if !(defined __GLIBC__ && !defined __UCLIBC__)
-# include <stddef.h>
-# include <stdio.h>
-# include <time.h>
-#endif
-#include <wchar.h>
-            int verify[sizeof (wint_t) < sizeof (int) ? -1 : 1];
+         [AC_LANG_PROGRAM(
+            [[#include <wchar.h>
+              int verify[sizeof (wint_t) < sizeof (int) ? -1 : 1];
             ]])],
          [gl_cv_type_wint_t_large_enough=yes],
          [gl_cv_type_wint_t_large_enough=no])])
diff --git a/m4/wmemchr.m4 b/m4/wmemchr.m4
index 62bd89ca54..79dc6abebe 100644
--- a/m4/wmemchr.m4
+++ b/m4/wmemchr.m4
@@ -1,4 +1,4 @@
-# wmemchr.m4 serial 4
+# wmemchr.m4 serial 5
 dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,16 +11,9 @@ AC_DEFUN([gl_FUNC_WMEMCHR],
   dnl provide this function as an inline function definition.
   AC_CACHE_CHECK([for wmemchr], [gl_cv_func_wmemchr],
     [AC_LINK_IFELSE(
-       [AC_LANG_PROGRAM([[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
-   before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]],
+       [AC_LANG_PROGRAM(
+          [[#include <wchar.h>
+          ]],
           [[return ! wmemchr ((const wchar_t *) 0, (wchar_t) ' ', 0);]])
        ],
        [gl_cv_func_wmemchr=yes],
diff --git a/m4/wmemcmp.m4 b/m4/wmemcmp.m4
index 701e73fe20..31d5ee3cda 100644
--- a/m4/wmemcmp.m4
+++ b/m4/wmemcmp.m4
@@ -1,4 +1,4 @@
-# wmemcmp.m4 serial 4
+# wmemcmp.m4 serial 5
 dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,16 +11,9 @@ AC_DEFUN([gl_FUNC_WMEMCMP],
   dnl provide this function as an inline function definition.
   AC_CACHE_CHECK([for wmemcmp], [gl_cv_func_wmemcmp],
     [AC_LINK_IFELSE(
-       [AC_LANG_PROGRAM([[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
-   before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]],
+       [AC_LANG_PROGRAM(
+          [[#include <wchar.h>
+          ]],
           [[return ! wmemcmp ((const wchar_t *) 0, (const wchar_t *) 0, 0);]])
        ],
        [gl_cv_func_wmemcmp=yes],
diff --git a/m4/wmemcpy.m4 b/m4/wmemcpy.m4
index c9d749d689..52b9ef1a95 100644
--- a/m4/wmemcpy.m4
+++ b/m4/wmemcpy.m4
@@ -1,4 +1,4 @@
-# wmemcpy.m4 serial 4
+# wmemcpy.m4 serial 5
 dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,16 +11,9 @@ AC_DEFUN([gl_FUNC_WMEMCPY],
   dnl provide this function as an inline function definition.
   AC_CACHE_CHECK([for wmemcpy], [gl_cv_func_wmemcpy],
     [AC_LINK_IFELSE(
-       [AC_LANG_PROGRAM([[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
-   before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]],
+       [AC_LANG_PROGRAM(
+          [[#include <wchar.h>
+          ]],
           [[return ! wmemcpy ((wchar_t *) 0, (const wchar_t *) 0, 0);]])
        ],
        [gl_cv_func_wmemcpy=yes],
diff --git a/m4/wmemmove.m4 b/m4/wmemmove.m4
index adbc12d779..d7b3d32919 100644
--- a/m4/wmemmove.m4
+++ b/m4/wmemmove.m4
@@ -1,4 +1,4 @@
-# wmemmove.m4 serial 4
+# wmemmove.m4 serial 5
 dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,16 +11,9 @@ AC_DEFUN([gl_FUNC_WMEMMOVE],
   dnl provide this function as an inline function definition.
   AC_CACHE_CHECK([for wmemmove], [gl_cv_func_wmemmove],
     [AC_LINK_IFELSE(
-       [AC_LANG_PROGRAM([[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
-   before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]],
+       [AC_LANG_PROGRAM(
+          [[#include <wchar.h>
+          ]],
           [[return ! wmemmove ((wchar_t *) 0, (const wchar_t *) 0, 0);]])
        ],
        [gl_cv_func_wmemmove=yes],
diff --git a/m4/wmemset.m4 b/m4/wmemset.m4
index 0148ea301a..9b89ebf12a 100644
--- a/m4/wmemset.m4
+++ b/m4/wmemset.m4
@@ -1,4 +1,4 @@
-# wmemset.m4 serial 4
+# wmemset.m4 serial 5
 dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,16 +11,9 @@ AC_DEFUN([gl_FUNC_WMEMSET],
   dnl provide this function as an inline function definition.
   AC_CACHE_CHECK([for wmemset], [gl_cv_func_wmemset],
     [AC_LINK_IFELSE(
-       [AC_LANG_PROGRAM([[
-/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
-   <wchar.h>.
-   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
-   before <wchar.h>.  */
-#include <stddef.h>
-#include <stdio.h>
-#include <time.h>
-#include <wchar.h>
-]],
+       [AC_LANG_PROGRAM(
+          [[#include <wchar.h>
+          ]],
           [[return ! wmemset ((wchar_t *) 0, (wchar_t) ' ', 0);]])
        ],
        [gl_cv_func_wmemset=yes],