Fix windows compilation

Change-Id: Id65e6e915ef7e3d7f3be0858e2ff534cf5ad1a03
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>

src/plugins/projectexplorer/devicesupport/desktopdeviceprocess.cpp

@@ -61,7 +61,7 @@ void DesktopDeviceProcess::interrupt()
 {
 #ifdef Q_OS_UNIX
     ::kill(m_process->pid(), SIGINT);
-#elif Q_OS_WIN
+#elif defined(Q_OS_WIN)
     // tbd
 #endif
 }