machine file: Fix parenthesized expressions

Extends 79ed2415e9. Thanks @bruchar1 for the test case; I got
absolutely lost trying to figure out where to add one.

mesonbuild/coredata.py

@@ -1097,6 +1097,8 @@ class MachineFileParser():
             return node.value
         elif isinstance(node, mparser.NumberNode):
             return node.value
+        elif isinstance(node, mparser.ParenthesizedNode):
+            return self._evaluate_statement(node.inner)
         elif isinstance(node, mparser.ArrayNode):
             # TODO: This is where recursive types would come in handy
             return [self._evaluate_statement(arg) for arg in node.args.arguments]

test cases/common/222 native prop/nativefile.ini

@@ -1,3 +1,4 @@
 [properties]
 astring = 'mystring'
-anarray = ['one', 'two']
+anarray = ['one', 'two']
+withparentheses = ('anotherstring')  # Ensure parentheses can be parsed