Zend/zend_variables: use C99 designated initializers (#10655)

This change allows to potentially turn the ``IS_`` macros into an enum with automatic values.

Author: MaxKellermann

Zend/zend_variables.c

@@ -37,18 +37,18 @@ static void ZEND_FASTCALL zend_empty_destroy(zend_reference *ref);
 typedef void (ZEND_FASTCALL *zend_rc_dtor_func_t)(zend_refcounted *p);
 
 static const zend_rc_dtor_func_t zend_rc_dtor_func[] = {
-	/* IS_UNDEF        */ (zend_rc_dtor_func_t)zend_empty_destroy,
-	/* IS_NULL         */ (zend_rc_dtor_func_t)zend_empty_destroy,
-	/* IS_FALSE        */ (zend_rc_dtor_func_t)zend_empty_destroy,
-	/* IS_TRUE         */ (zend_rc_dtor_func_t)zend_empty_destroy,
-	/* IS_LONG         */ (zend_rc_dtor_func_t)zend_empty_destroy,
-	/* IS_DOUBLE       */ (zend_rc_dtor_func_t)zend_empty_destroy,
-	/* IS_STRING       */ (zend_rc_dtor_func_t)zend_string_destroy,
-	/* IS_ARRAY        */ (zend_rc_dtor_func_t)zend_array_destroy,
-	/* IS_OBJECT       */ (zend_rc_dtor_func_t)zend_objects_store_del,
-	/* IS_RESOURCE     */ (zend_rc_dtor_func_t)zend_list_free,
-	/* IS_REFERENCE    */ (zend_rc_dtor_func_t)zend_reference_destroy,
-	/* IS_CONSTANT_AST */ (zend_rc_dtor_func_t)zend_ast_ref_destroy
+	[IS_UNDEF] =        (zend_rc_dtor_func_t)zend_empty_destroy,
+	[IS_NULL] =         (zend_rc_dtor_func_t)zend_empty_destroy,
+	[IS_FALSE] =        (zend_rc_dtor_func_t)zend_empty_destroy,
+	[IS_TRUE] =         (zend_rc_dtor_func_t)zend_empty_destroy,
+	[IS_LONG] =         (zend_rc_dtor_func_t)zend_empty_destroy,
+	[IS_DOUBLE] =       (zend_rc_dtor_func_t)zend_empty_destroy,
+	[IS_STRING] =       (zend_rc_dtor_func_t)zend_string_destroy,
+	[IS_ARRAY] =        (zend_rc_dtor_func_t)zend_array_destroy,
+	[IS_OBJECT] =       (zend_rc_dtor_func_t)zend_objects_store_del,
+	[IS_RESOURCE] =     (zend_rc_dtor_func_t)zend_list_free,
+	[IS_REFERENCE] =    (zend_rc_dtor_func_t)zend_reference_destroy,
+	[IS_CONSTANT_AST] = (zend_rc_dtor_func_t)zend_ast_ref_destroy
 };
 
 ZEND_API void ZEND_FASTCALL rc_dtor_func(zend_refcounted *p)