gui: Tcl_Interp is a struct not a class

Signed-off-by: Anton Blanchard <[email protected]>

Author: antonblanchard

src/gui/src/scriptWidget.h

@@ -43,7 +43,7 @@ namespace odb {
 class dbDatabase;
 }  // namespace odb
 
-class Tcl_Interp;
+struct Tcl_Interp;
 
 namespace gui {
 class TclCmdInputWidget;