Test [[ and ]] in string literal are preserved

Suggested by wsfulton in #1158

Examples/test-suite/cpp11_attribute_specifiers.i

@@ -38,4 +38,6 @@ bool maybeUnused2(bool a, [[maybe_unused]] bool b) { return a; }
 
 struct [[nodiscard]] S { };
 
+const char *test_string_literal() { return "Test [[ and ]] in string literal"; }
+
 %}

Examples/test-suite/php/cpp11_attribute_specifiers_runme.php

@@ -0,0 +1,14 @@
+<?php
+
+require "tests.php";
+
+// New functions
+check::functions(array('noReturn','noDiscard','noDiscardDeprecated','maybeUnused1','maybeUnused2','likely','test_string_literal'));
+// New classes
+check::classes(array('cpp11_attribute_specifiers','S'));
+// No new vars
+check::globals(array());
+
+check::equal(test_string_literal(), 'Test [[ and ]] in string literal', "test_string_literal() wrong");
+
+check::done();