Windows: Link to Dwmapi.lib via pragma

So I don't have to figure out some exotic non-cmake build systems

It's more self-contained this way anyway.

src/private/WidgetResizeHandler.cpp

@@ -33,6 +33,7 @@
 # include <windows.h>
 # include <dwmapi.h>
 # if defined(Q_CC_MSVC)
+#  pragma comment(lib,"Dwmapi.lib")
 #  pragma comment(lib,"User32.lib")
 # endif
 #endif