wcwidth: Document MidnightBSD bug

[Bruno Haible]

The result of configure tests on MidnightBSD 1.1 shows that this platform
has the same bugs as NetBSD. This patch documents it.


2021-02-07  Bruno Haible  <bruno@clisp.org>

        wcwidth: Document MidnightBSD bug.
        * doc/posix-functions/wcwidth.texi: Mention MidnightBSD as an affected
        platform.
        * m4/wcwidth.m4 (gl_FUNC_WCWIDTH): Update comments.

diff --git a/doc/posix-functions/wcwidth.texi b/doc/posix-functions/wcwidth.texi
index 86d2397..0540bb6 100644
--- a/doc/posix-functions/wcwidth.texi
+++ b/doc/posix-functions/wcwidth.texi
@@ -17,7 +17,7 @@ glibc 2.8.
 @item
 This function handles combining characters in UTF-8 locales incorrectly on some
 platforms:
-NetBSD 9.0, OpenBSD 5.8.
+NetBSD 9.0, OpenBSD 5.8, MidnightBSD 1.1.
 @item
 This function returns 2 for characters with ambiguous east asian width, even in
 Western locales, on some platforms:
diff --git a/m4/wcwidth.m4 b/m4/wcwidth.m4
index 40fdea7..2ac2a51 100644
--- a/m4/wcwidth.m4
+++ b/m4/wcwidth.m4
@@ -1,4 +1,4 @@
-# wcwidth.m4 serial 33
+# wcwidth.m4 serial 34
 dnl Copyright (C) 2006-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -41,8 +41,10 @@ AC_DEFUN([gl_FUNC_WCWIDTH],
   if test $ac_cv_func_wcwidth = yes || test $gl_cv_func_wcwidth_macro = yes; 
then
     HAVE_WCWIDTH=1
     dnl On Mac OS X 10.3, wcwidth(0x0301) (COMBINING ACUTE ACCENT) returns 1.
-    dnl On NetBSD 9.0, OpenBSD 5.0, wcwidth(0x05B0) (HEBREW POINT SHEVA) 
returns 1.
-    dnl On NetBSD 9.0, OSF/1 5.1, wcwidth(0x200B) (ZERO WIDTH SPACE) returns 1.
+    dnl On NetBSD 9.0, OpenBSD 5.0, MidnightBSD 1.1,
+    dnl wcwidth(0x05B0) (HEBREW POINT SHEVA) returns 1.
+    dnl On NetBSD 9.0, MidnightBSD 1.1, OSF/1 5.1,
+    dnl wcwidth(0x200B) (ZERO WIDTH SPACE) returns 1.
     dnl On OpenBSD 5.8, wcwidth(0xFF1A) (FULLWIDTH COLON) returns 0.
     dnl This leads to bugs in 'ls' (coreutils).
     dnl On Solaris 11.4, wcwidth(0x2202) (PARTIAL DIFFERENTIAL) returns 2,