[PATCH] stdbool-c99: fix typo

[Paul Eggert]

Reported against Autoconf by Todd C. Miller in:
https://lists.gnu.org/r/autoconf/2022-12/msg00001.html
* m4/stdbool.m4 (AC_CHECK_HEADER_STDBOOL): Sync from Autoconf master.
---
 ChangeLog     |  7 +++++++
 m4/stdbool.m4 | 12 ++++++------
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index b4f752c448..d81bde3f8d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2022-12-26  Paul Eggert  <eggert@cs.ucla.edu>
+
+       stdbool-c99: fix typo
+       Reported against Autoconf by Todd C. Miller in:
+       https://lists.gnu.org/r/autoconf/2022-12/msg00001.html
+       * m4/stdbool.m4 (AC_CHECK_HEADER_STDBOOL): Sync from Autoconf master.
+
 2022-12-26  Bruno Haible  <bruno@clisp.org>
 
        ctime: Mark as deprecated, not obsolete. (Regression 2022-12-21.)
diff --git a/m4/stdbool.m4 b/m4/stdbool.m4
index c67908aa87..18fe4b874f 100644
--- a/m4/stdbool.m4
+++ b/m4/stdbool.m4
@@ -5,7 +5,7 @@ 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.
 
-#serial 9
+#serial 10
 
 # Prepare for substituting <stdbool.h> if it is not supported.
 
@@ -57,10 +57,10 @@ AC_DEFUN([AC_CHECK_HEADER_STDBOOL],
                 integer constant expressions, and "bool" should be a valid
                 type name.
 
-                Although C 1999 requires bool, true, and false to be macros,
-                C 2023 and C++ 2011 overrule that, so do not test for that.
-                Although C 1999 requires __bool_true_false_are_defined and
-                _Bool, C 2023 says they are obsolescent, so do not require
+                Although C99 requires bool, true, and false to be macros,
+                C23 and C++11 overrule that, so do not test for that.
+                Although C99 requires __bool_true_false_are_defined and
+                _Bool, C23 says they are obsolescent, so do not require
                 them.  */
 
              #if !true
@@ -108,7 +108,7 @@ AC_DEFUN([AC_CHECK_HEADER_STDBOOL],
 
              /* Refer to every declared value, so they cannot be
                 discarded as unused.  */
-             return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !j + !k
+             return (!b + !c + !d + !e + !f + !g + !h + !i + !j + !k
                      + !l + !m + !n + !o + !p + !pp + !ps);
            ]])],
         [ac_cv_header_stdbool_h=yes],
-- 
2.38.1