Use qtcbuildhelper for starting the build process on Windows.

Task-number: QTCREATORBUG-4558

Change-Id: Ib6f5be80f034135bbd8c45a22e223e758cc7e7b1
Reviewed-on: http://codereview.qt.nokia.com/2555
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@nokia.com>

src/plugins/projectexplorer/abstractprocessstep.cpp

@@ -189,6 +189,7 @@ void AbstractProcessStep::run(QFutureInterface<bool> &fi)
         wd.mkpath(wd.absolutePath());
 
     m_process = new Utils::QtcProcess();
+    m_process->setUseCtrlCStub(true);
     m_process->setWorkingDirectory(wd.absolutePath());
     m_process->setEnvironment(m_param.environment());