mbrtoc32: Fix a cross-compilation guess

[Bruno Haible]

This patch fixes a harmless typo in a configure test.


2024-08-31  Bruno Haible  <bruno@clisp.org>

        mbrtoc32: Fix a cross-compilation guess.
        * m4/mbrtoc32.m4 (gl_MBRTOC32_UTF8_LOCALE): Guess no on Cygwin.

diff --git a/m4/mbrtoc32.m4 b/m4/mbrtoc32.m4
index 8118ff8f29..4da0712bd4 100644
--- a/m4/mbrtoc32.m4
+++ b/m4/mbrtoc32.m4
@@ -1,5 +1,5 @@
 # mbrtoc32.m4
-# serial 20
+# serial 21
 dnl Copyright (C) 2014-2024 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -213,7 +213,7 @@ AC_DEFUN([gl_MBRTOC32_UTF8_LOCALE]
        [gl_cv_func_mbrtoc32_utf8_locale_works=no],
        [case "$host_os" in
                    # Guess no on Cygwin.
-          cygwin*) gl_cv_func_mbrtoc32_utf8_locale_works="guessing yes" ;;
+          cygwin*) gl_cv_func_mbrtoc32_utf8_locale_works="guessing no" ;;
           *)       
gl_cv_func_mbrtoc32_utf8_locale_works="$gl_cross_guess_normal" ;;
         esac
        ])