Centralize S60 check, also use it for adding the GDB TRK page.

qtcreator.pri

@@ -108,3 +108,7 @@ linux-g++-* {
     # to prevent checking in code that does not compile on other platforms.
     QMAKE_LFLAGS += -Wl,--allow-shlib-undefined -Wl,--no-undefined
 }
+
+# Handle S60 support: default on Windows, conditionally built on other platforms.
+win32:SUPPORT_QT_S60=1
+else:SUPPORT_QT_S60 = $$(QTCREATOR_WITH_S60)

src/plugins/debugger/gdb/gdb.pri

 include(../../../shared/trk/trk.pri)
 
+!isEmpty(SUPPORT_QT_S60) {
+    message("Adding experimental support for Qt/S60 applications.")
+    DEFINES += QTCREATOR_WITH_S60
+}
+
 HEADERS += \
     $$PWD/gdbmi.h \
     $$PWD/gdbengine.h \

src/plugins/debugger/gdb/gdbengine.cpp

@@ -4227,8 +4227,9 @@ void GdbEngine::handleAdapterShutdownFailed(const QString &msg)
 void GdbEngine::addOptionPages(QList<Core::IOptionsPage*> *opts) const
 {
     opts->push_back(new GdbOptionsPage);
-    if (!qgetenv("QTCREATOR_WITH_S60").isEmpty())
+#ifdef QTCREATOR_WITH_S60
         opts->push_back(new TrkOptionsPage(m_trkAdapter->options()));
+#endif
 }
 
 void GdbEngine::showMessageBox(int icon, const QString &title, const QString &text)

src/plugins/qt4projectmanager/qt-s60/qt-s60.pri

-win32:SUPPORT_QT_S60=1
-else:SUPPORT_QT_S60 = $$(QTCREATOR_WITH_S60)
 !isEmpty(SUPPORT_QT_S60) {
     message("Adding experimental support for Qt/S60 applications.")
     DEFINES += QTCREATOR_WITH_S60