C++: fix macro calls with comment before arguments

When in 'keep comments' mode, the preprocessor does not properly handle macro calls with
comments between the macro name and the opening parenthesis: "FOO /*something to say*/
(45)".

Change-Id: I6fe733242e4d2ccff2985d17399d0a084917415a
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/libs/cplusplus/pp-engine.cpp

@@ -1330,6 +1330,13 @@ bool Preprocessor::collectActualArguments(PPToken *tk, QVector<QVector<PPToken>
 
     lex(tk); // consume the identifier
 
+    // consume comments
+    while (tk->isComment()) {
+        lex(tk);
+        if (!tk)
+            return false;
+    }
+
     if (tk->isNot(T_LPAREN))
         //### TODO: error message
         return false;