Merge branch 'PHP-8.1'

* PHP-8.1:
  Fix pcntl Haiku build

Author: cmb69

ext/pcntl/pcntl.c

@@ -152,7 +152,9 @@ void php_register_signal_constants(INIT_FUNC_ARGS)
 #ifdef SIGPOLL
 	REGISTER_LONG_CONSTANT("SIGPOLL",  (zend_long) SIGPOLL, CONST_CS | CONST_PERSISTENT);
 #endif
+#ifdef SIGIO
 	REGISTER_LONG_CONSTANT("SIGIO",    (zend_long) SIGIO, CONST_CS | CONST_PERSISTENT);
+#endif
 #ifdef SIGPWR
 	REGISTER_LONG_CONSTANT("SIGPWR",   (zend_long) SIGPWR, CONST_CS | CONST_PERSISTENT);
 #endif