Fix build: add necessary includes

starmath/source/dialog.cxx needs vcl/combobox.hxx to use
COMBOBOX_ENTRY_NOTFOUND define.

vcl/virdev.hxx is needed to know VirtualDevice ancestors to allow
assignments to pointers to OutputDevice.

Change-Id: Iafd33081ef33f28697e9a03bd4892a781fb2eb27
Reviewed-on: https://gerrit.libreoffice.org/65925Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>
Tested-by: Mike Kaganski <mike.kaganski@collabora.com>

starmath/source/dialog.cxx

@@ -26,6 +26,8 @@
 #include <svl/eitem.hxx>
 #include <svl/intitem.hxx>
 #include <svl/stritem.hxx>
+#include <vcl/combobox.hxx>
+#include <vcl/virdev.hxx>
 #include <vcl/weld.hxx>
 #include <svtools/ctrltool.hxx>
 #include <vcl/settings.hxx>

starmath/source/document.cxx

@@ -53,6 +53,7 @@
 #include <editeng/fhgtitem.hxx>
 #include <editeng/fontitem.hxx>
 #include <vcl/mapmod.hxx>
+#include <vcl/virdev.hxx>
 #include <tools/mapunit.hxx>
 #include <vcl/settings.hxx>
 

starmath/source/view.cxx

@@ -54,6 +54,7 @@
 #include <vcl/decoview.hxx>
 #include <vcl/menu.hxx>
 #include <vcl/settings.hxx>
+#include <vcl/virdev.hxx>
 #include <sal/log.hxx>
 
 #include <unotools/streamwrap.hxx>