Add GdkEventKey declaration fix PCH-less build.

Declare it in wx/gtk/textentry.h too, not only wx/gtk/window.h.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73707 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/textentry.h

@@ -11,6 +11,7 @@
 #ifndef _WX_GTK_TEXTENTRY_H_
 #define _WX_GTK_TEXTENTRY_H_
 
+typedef struct _GdkEventKey GdkEventKey;
 typedef struct _GtkEditable GtkEditable;
 typedef struct _GtkEntry GtkEntry;