Move qtvirtualkeyboard over to the new configure system

Adjust configuration from passing lots of CONFIG+=... on the qmake
command line to proper command line arguments. Add configure tests for
external libraries we might end up using.

Adjusted the build documentation to reflect the new way of configuring.

Replace all custom HAVE_FOO feature defines with proper
QT_CONFIG() checks.

This patch does not handle the options -disable-hunspell,
-no-bundle-ctime and -no-bundle-pinyin as they are not a necessity to
properly support the CMake port and can be added later.

[ChangeLog][Important Behavior Changes] The build system was switched to
the new configure system. See documentation for updated instructions.

Change-Id: I52f863a4d0217bde38fa3fc5e5967b7d8dcb06e0
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

2 files changed, 44 insertions, 0 deletions

diff --git a/config.tests/hunspell/hunspell.pro b/config.tests/hunspell/hunspell.pro
new file mode 100644
index 00000000..28dcadcb
--- /dev/null
+++ b/config.tests/hunspell/hunspell.pro
@@ -0,0 +1 @@
+SOURCES += main.cpp
diff --git a/config.tests/hunspell/main.cpp b/config.tests/hunspell/main.cpp
new file mode 100644
index 00000000..d37e6983
--- /dev/null
+++ b/config.tests/hunspell/main.cpp
@@ -0,0 +1,43 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the Qt Virtualkeyboard module
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** 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 The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/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 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later 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 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <hunspell/hunspell.h>
+
+int main(int argc, char** argv)
+{
+    Hunspell_create(0, 0);
+    return 0;
+}