Fix moc stumbling over gcc __attribute__ extensions

Reported by David Faure.

In KDE a DEPRECATED macro gets defined in a header file created by cmake.
The define is not guarded with #if Q_CC_GNU or similar because at cmake
time the compiler is determined. Therefore moc suddenly sees this gcc
specific token and stumbles over it.

This patch simply defines an empty __attribute__ macro that will expand
to nothing and thus become invisible to moc's "C++ parser" after the
pre-processing.

Change-Id: I4448b9ac3f72b6334e32b27484401fb0fca23a0c
Reviewed-by: David Faure <faure@kde.org>
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>

src/tools/moc/main.cpp

@@ -170,6 +170,14 @@ int runMoc(int _argc, char **_argv)
     Moc moc;
     pp.macros["Q_MOC_RUN"];
     pp.macros["__cplusplus"];
+
+    // Don't stumble over GCC extensions
+    Macro dummyVariadicFunctionMacro;
+    dummyVariadicFunctionMacro.isFunction = true;
+    dummyVariadicFunctionMacro.isVariadic = true;
+    dummyVariadicFunctionMacro.arguments += Symbol(0, PP_IDENTIFIER, "__VA_ARGS__");
+    pp.macros["__attribute__"] = dummyVariadicFunctionMacro;
+
     QByteArray filename;
     QByteArray output;
     FILE *in = 0;

tests/auto/tools/moc/function-with-attributes.h

@@ -0,0 +1,57 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+#include <qobject.h>
+
+// test support for gcc attributes with functions
+
+#if defined(Q_CC_GNU) || defined(Q_MOC_RUN)
+#define DEPRECATED __attribute__ ((__deprecated__))
+#else
+#define DEPRECATED
+#endif
+
+class FunctionWithAttributes : public QObject
+{
+    Q_OBJECT
+public slots:
+    DEPRECATED void test() {}
+
+};

tests/auto/tools/moc/moc.pro

@@ -22,7 +22,8 @@ HEADERS += using-namespaces.h no-keywords.h task87883.h c-comments.h backslash-n
            cxx11-final-classes.h \
            cxx11-explicit-override-control.h \
            forward-declared-param.h \
-           parse-defines.h
+           parse-defines.h \
+           function-with-attributes.h
 
 
 if(*-g++*|*-icc*|*-clang*|*-llvm):!irix-*:!win32-*: HEADERS += os9-newlines.h win-newlines.h