Fixes for wxQt build under Cygwin

Include the missing headers, notable QtGui/QFont from wx/fontutil.h which uses
a QFont object.

Closes #16750.

src/qt/bitmap.cpp

@@ -8,16 +8,25 @@
 // For compilers that support precompilation, includes "wx.h".
 #include "wx/wxprec.h"
 
-#include "wx/bitmap.h"
-#include "wx/image.h"
-#include "wx/rawbmp.h"
-#include "wx/qt/private/converter.h"
-#include "wx/qt/private/utils.h"
+#ifdef __BORLANDC__
+    #pragma hdrstop
+#endif
 
 #include <QtGui/QPixmap>
 #include <QtGui/QBitmap>
 #include <QtWidgets/QLabel>
 
+#ifndef WX_PRECOMP
+    #include "wx/icon.h"
+    #include "wx/image.h"
+#endif // WX_PRECOMP
+
+#include "wx/bitmap.h"
+#include "wx/rawbmp.h"
+#include "wx/qt/private/converter.h"
+#include "wx/qt/private/utils.h"
+
+
 static wxImage ConvertImage( QImage qtImage )
 {
     bool hasAlpha = qtImage.hasAlphaChannel();