CMake: Use radio buttons to select build targets

Use radio buttons to select build targets in CMakeBuildStep.

CMake only allows for one target to be built at one time, so checkboxes
are confusing.

Task-number: QTCREATORBUG-20764
Change-Id: I1171abd1753817595562526456c3ce613a22667c
Reviewed-by: Cristian Adam <cristian.adam@qt.io>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/cmakeprojectmanager/cmakebuildstep.h

@@ -33,6 +33,7 @@ QT_BEGIN_NAMESPACE
 class QLineEdit;
 class QListWidget;
 class QListWidgetItem;
+class QRadioButton;
 QT_END_NAMESPACE
 
 namespace Utils {
@@ -130,7 +131,9 @@ private:
     void toolArgumentsEdited();
     void updateDetails();
     void buildTargetsChanged();
-    void selectedBuildTargetsChanged();
+    void updateBuildTarget();
+
+    QRadioButton *itemWidget(QListWidgetItem *item);
 
     CMakeBuildStep *m_buildStep;
     QLineEdit *m_toolArguments;