Quiet gcc warnings on glibc systems that use warn_unused_result for

write(2) and others.

plugins/sudoers/logging.c

@@ -452,7 +452,8 @@ send_mail(const char *fmt, ...)
     /* Daemonize - disassociate from session/tty. */
     if (setsid() == -1)
       warning("setsid");
-    (void) chdir("/");
+    if (chdir("/") == -1)
+      warning("chdir(/)");
     if ((fd = open(_PATH_DEVNULL, O_RDWR, 0644)) != -1) {
 	(void) dup2(fd, STDIN_FILENO);
 	(void) dup2(fd, STDOUT_FILENO);