Add wxUSE_MARKUP and wrap SetLabelMarkup() in it.

Make it possible to disable all the new markup-related code by setting
wxUSE_MARKUP to 0 in setup.h or using configure --disable-markup option.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67062 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/os2/setup0.h

@@ -714,6 +714,15 @@
 // Recommended setting: 1 (don't change except for very special programs)
 #define wxUSE_CONTROLS     1
 
+// Support markup in control labels, i.e. provide wxControl::SetLabelMarkup().
+// Currently markup is supported only by a few controls and only some ports but
+// their number will increase with time.
+//
+// Default is 1
+//
+// Recommended setting: 1 (may be set to 0 if you want to save on code size)
+#define wxUSE_MARKUP       1
+
 // wxPopupWindow class is a top level transient window. It is currently used
 // to implement wxTipWindow
 //