Handle postfix type qualifiers in compound literals

Fixes atom/language-c#312

corpus/expressions.txt

@@ -346,6 +346,7 @@ int main() {
     7,
     8
   };
+  z = (char const []) {'a', 'b'};
 }
 
 ---
@@ -374,7 +375,13 @@ int main() {
           (type_descriptor (struct_specifier (type_identifier)))
           (initializer_list
             (number_literal)
-            (number_literal))))))))
+            (number_literal)))))
+      (expression_statement
+        (assignment_expression
+          (identifier)
+          (compound_literal_expression
+            (type_descriptor (primitive_type) (type_qualifier) (abstract_array_declarator))
+            (initializer_list (char_literal) (char_literal))))))))
 
 ============================================
 Compound literals with trailing commas

grammar.js

@@ -600,6 +600,7 @@ module.exports = grammar({
     type_descriptor: $ => seq(
       repeat($.type_qualifier),
       $._type_specifier,
+      repeat($.type_qualifier),
       optional($._abstract_declarator)
     ),
 

src/grammar.json

@@ -3399,6 +3399,13 @@
           "type": "SYMBOL",
           "name": "_type_specifier"
         },
+        {
+          "type": "REPEAT",
+          "content": {
+            "type": "SYMBOL",
+            "name": "type_qualifier"
+          }
+        },
         {
           "type": "CHOICE",
           "members": [