[PATCH] autoconf: drop obsolete unused stdbool.h check

[Rudi Heitbaum <rudi@heitbaum.com>]

With configure as shipped using GNU Autoconf 2.69 for cifs-utils 7.1
configure fails when compiling with -std=c23 (gcc 15):

    checking for stdbool.h... (cached) no
    configure: error: necessary header(s) not found

Using GNU Autoconf 2.72 to create the configure file does allow the build
to complete, but as the HAVE_STDBOOL_H is unused - drop the check entirely.

Link: https://www.gnu.org/software/autoconf/manual/autoconf-2.72/html_node/Particular-Headers.html

Signed-off-by: Rudi Heitbaum <rudi@heitbaum.com>
---
 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index b84c41f..47c6069 100644
--- a/configure.ac
+++ b/configure.ac
@@ -127,7 +127,7 @@ AC_CHECK_FUNCS(clock_gettime, [], [
 AC_SUBST(RT_LDADD)
 
 # Checks for header files.
-AC_CHECK_HEADERS([arpa/inet.h ctype.h fcntl.h inttypes.h limits.h mntent.h netdb.h stddef.h stdint.h stdbool.h stdlib.h stdio.h errno.h string.h strings.h sys/mount.h sys/param.h sys/socket.h sys/time.h syslog.h unistd.h], , [AC_MSG_ERROR([necessary header(s) not found])])
+AC_CHECK_HEADERS([arpa/inet.h ctype.h fcntl.h inttypes.h limits.h mntent.h netdb.h stddef.h stdint.h stdlib.h stdio.h errno.h string.h strings.h sys/mount.h sys/param.h sys/socket.h sys/time.h syslog.h unistd.h], , [AC_MSG_ERROR([necessary header(s) not found])])
 
 # do we have sys/fsuid.h and setfsuid()?
 AC_CHECK_HEADERS([sys/fsuid.h])
-- 
2.43.0