Don't register an event handler for EVT_STC_CLIPBOARD_PASTE on
wxWidgets versions less than 3.1.0, where it is not defined. This unblocks further development for Fedora Core, whose most recent wxWidgets library is 3.0.2.
Authored by: david_costanzo 2016-07-17
Parent: [r4173]
Child: [r4175]
