gui+qnx: enable QClipboard on QNX (BB10)

Upstream Qt gates the clipboard feature off on QNX
(CONDITION ... AND NOT QNX), so QGuiApplication::clipboard() / QClipboard
disappear and tdesktop (which uses clipboard in ~50 files) can't build.
Allow the feature on QNX.

The qqnx platform plugin ships a working QQnxClipboard (built when
QT_FEATURE_qqnx_pps, links libclipboard which the QNX 8 sysroot provides),
but it had bit-rotted while the feature was off: Qt 6.8.3 no longer pulls
QLoggingCategory/QSet transitively, so add the missing includes to
qqnxclipboard.{h,cpp}.

Build with -DFEATURE_clipboard=ON.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/gui/configure.cmake

@@ -1082,7 +1082,10 @@ qt_feature("clipboard" PUBLIC
     SECTION "Kernel"
     LABEL "QClipboard"
     PURPOSE "Provides cut and paste operations."
-    CONDITION NOT INTEGRITY AND NOT QNX AND NOT rtems
+    # BB10: upstream gates clipboard off on QNX, but the qqnx plugin ships a
+    # working QQnxClipboard (built when QT_FEATURE_qqnx_pps, links libclipboard
+    # which the QNX sysroot provides). tdesktop needs QClipboard, so allow it.
+    CONDITION NOT INTEGRITY AND NOT rtems
 )
 qt_feature_definition("clipboard" "QT_NO_CLIPBOARD" NEGATE VALUE "1")
 qt_feature("wheelevent" PUBLIC

src/plugins/platforms/qnx/qqnxclipboard.cpp

@@ -10,7 +10,9 @@
 #include <QtGui/QColor>
 
 #include <QtCore/QDebug>
+#include <QtCore/QLoggingCategory>
 #include <QtCore/QMimeData>
+#include <QtCore/QSet>
 #include <QtCore/QStringList>
 #include <QtCore/QUrl>
 

src/plugins/platforms/qnx/qqnxclipboard.h

@@ -8,6 +8,7 @@
 
 #if !defined(QT_NO_CLIPBOARD)
 #include <qpa/qplatformclipboard.h>
+#include <QtCore/QLoggingCategory>
 
 QT_BEGIN_NAMESPACE